Sofia Jonsson

The cost-effectiveness of Gastric bypass surgery as a treatment for

severe obesity

Economics Master’s Thesis

Date/Term: Spring 2013

Supervisor: Mikael Svensson

Examiner: Björn Sund

I

Abstract

This paper analyzes the cost-effectiveness, measured in cost per quality-adjusted life year

(QALY), of the surgical method Gastric Bypass as a treatment for obesity in comparison to

not performing Gastric bypass. Data was obtained from the hospital in Värmland (Torsby),

Sweden, that performs Gastric bypass surgery on severely obese individuals and from

literature studies.

A decision-tree analysis was conducted identifying probabilities, costs and utilities with the

treatment and non-treatment alternative. The incremental cost-effectiveness ratio (ICER) for

the base case resulted in -19 562 951 SEK per QALY, i.e. the treatment is cost-saving and

produces more QALYs than no surgical treatment. A sensitivity analysis was performed with

Monte Carlo simulation of 5 000 cases. Given the assumptions made in this study the

simulation resulted in all the ICERs being cost saving. In summary, Gastric bypass was

shown to be very economically efficient, leading to cost-savings as well as improved health.

Keywords: obesity, Gastric bypass, cost-effectiveness analysis, Quality-adjusted life years

(QALY)

II

Contents

1. Introduction ............................................................................................................................ 1

1.1 Problem discussion ........................................................................................................... 3

1.2 Purpose ............................................................................................................................. 3

1.3 Method .............................................................................................................................. 3

1.4 Limitations ........................................................................................................................ 4

1.5 Disposition ........................................................................................................................ 4

2. Theoretical framework ........................................................................................................... 5

2.1 Economic theory ............................................................................................................... 5

3. Previous studies .................................................................................................................... 11

4. Model inputs ......................................................................................................................... 15

4.1 Data ................................................................................................................................. 16

4.1.1 Probabilities ............................................................................................................. 16

4.1.2 Costs ......................................................................................................................... 17

4.1.3 Quality-adjusted life years (QALYs) ....................................................................... 20

4.2 Sensitivity analysis ......................................................................................................... 21

5. Result .................................................................................................................................... 24

6. Discussion and Conclusion .................................................................................................. 26

References ................................................................................................................................ 28

APPENDIX .............................................................................................................................. 32

1

1. Introduction

In recent decades the prevalence of obesity has increased in many countries in the rich part of

the world. Between the years 1980/81 and 2005 the proportion of obese individuals has

increased from five percent to ten percent in Sweden (Persson & Ödegaard, 2011).

World Health Organization (2012) defines overweight and obesity as abnormal accumulation

of fat so severe that it affects health negatively. A commonly used index to determine

overweight and obesity among adults is the body mass index (BMI). Normal weight is

classified as a BMI of 18.5 kg/m2 to 24.9, whereas a BMI of 25 and over is classified as

overweight. BMI of 30 and over is classified as obesity and morbid obesity is BMI of over 40.

BMI is calculated as the weight of the individual in kilograms divided by the individual´s

squared length in meters (Parini & Nebiolo, 2004).

Overweight and obesity are more widespread in rich and industrialized countries (Parini &

Nebiolo, 2004). Researchers found a strong relationship between overweight and obesity and

a number of socio-environmental factors. In industrial countries obesity is also more

widespread among individual belonging to the lowest socioeconomic class (Parini & Nebiolo,

2004). Obesity is associated with a number of complications, such as Type-II diabetes1,

hypertension, dyslipidemia, cardiovascular disease, sleep apnea2, osteoarthrosis, renal failure

and several cancers (Faria et al., 2013). Reports have shown that the incidence of different

types of cancer can be reduced significantly by weight loss (NIOK, 2009). In epidemiological

studies the correlation between prevalence of obesity and prevalence of arthritis and muscle

problems is clear, and these problems are a common cause of sick leave in industrial countries

(NIOK, 2009). In addition to measuring obesity using BMI, it has also been shown that the

distribution of fat is important. Abdominal fat is associated with higher risk of cardiovascular

risk and disease (Parini & Nebiolo, 2004).

Individuals with obesity also experience lower health-related quality of life and more

psychosocial problems (even lower quality of life than patients with cancer (NIOK, 2009)).

1Diabetes of type II occurs due to decreased sensitivity to insulin in the tissue of the body and reduced

production of insulin (Parini & Nebiolo, 2004) 2Sleep apnea is pauses in breathing during sleep and the periods when the individual stops breathing can be so

long that the oxygen in the blood sinks to dangerously low levels (NIOK, 2009).

2

Mental illnesses such as depression and anxiety are more common among severely obese

individuals compared to the rest of the population (NIOK, 2009). According to NIOK (2009),

early retirement is more common among obese people than in the general population. Severe

obese people, especially young individuals, feel that social-networking and relationships are

enormously difficult. Travelling with public transport, finding clothes that fit and finding

suitable physical activity are other experienced difficulties (NIOK, 2009). Severe obese

individuals also experience discrimination and prejudiced reactions from the surroundings for

example discrimination in employment (NIOK, 2009).

There are three established treatment options for obesity; nutritional and behavior

modifications, pharmacological treatment and surgery (Campbell et al., 2010). In Sweden,

medical treatment is used although there are other potential treatments. Some potential

treatments could be regulations on the supply of fast food, nutrition- and exercise education or

exercise taxation on the overconsumption of food (Philipson & Posner, 2008). Physical

activity on prescription is a new and indirect method to overcome obesity (FHI, 2013). In

recent years there has been increased interest in surgical treatments for obesity. Surgical

treatments have shown to be effective in reducing overweight and obesity (Persson &

Ödegaard, 2011). However, surgical treatments have also proved to be expensive and cause a

high burden on the health care budget (Persson & Ödegaard, 2011). Obese patients have very

high consumption of medical care. In a review of patients waiting for bariatric surgery3 found

that patients on average had 22 contacts with other health care providers than the surgeon

years before surgery decision (NIOK, 2009) The cost of a Gastric bypass surgery was 60 000

SEK in 2011 (Landstinget i Värmland, 2013). And, according to the NIOK (2009) a

reasonable estimate of the average follow-up costs for the first year is 10 000, after which the

costs are not more than 2000 SEK / year. It should be noted that the cost of late reoperations,

hernia caused of incision and plastic surgery are not included in these figures. At the same

time, in 2003 the cost of obesity and overweight in Sweden was estimated to be around 16

billion SEK. Of those, 12.4 billion SEK was due to loss of production (Olofsson, 2008). The

direct costs of obesity and obesity related diseases were in Sweden 2003, two percent of all

medical care costs. This represents approximately 3 billion SEK (SBU, 2002).

3 Weight-loss surgery including the methods Gastric banding and Gastric bypass (WHO, 2011).

3

Ten year data from the Swedish Obese Study clearly shows that the surgical method Gastric

bypass gives larger and more sustained weight reduction compared to a control group. The

control group received conventional treatment. Maximum weight losses were observed after 1

to 2 years and were 32 percent from baseline for individuals who had Gastric bypass surgery.

After 10 years the weight loss was stabilized at 25 percent and after 15 years the

corresponding weight loss was observed to be 27 percent (Sjöström et al., 2007). In 2011

97.5 percent of the Swedish bariatric surgery was performed with the method Gastric bypass

and the remaining was done by other surgical methods, such as Gastric banding4 (SOReg,

2011).

1.1 Problem discussion

Increased degree of obesity leads to increased risk of consequential conditions such as

diseases (NIOK 2009). Obesity is a major health problem with both indirect and direct costs

to the individual and to society. Today, it becomes more common to treat obesity with Gastric

bypass surgery. In 2011 the number of bariatric surgeries was about 8600 in Sweden (SOReg,

2011). During 2008 the county council of Värmland had the highest number of surgeries per

100 000 population in Sweden (SKL, 2009). There are also indications that there is a need of

a much larger number of obesity surgeries than currently performed. The hospital in Torsby,

Sweden, is the only hospital in the county council of Värmlands that performs Gastric bypass

surgery on severely obese (Landstinget i Värmland, 2012). The major costs and health effects

of obesity and the increased use of Gastric bypass indicate that it is relevant and important to

analyze the cost-effectiveness with this treatment.

1.2 Purpose

This paper analyzes the cost-effectiveness, measured in cost per quality-adjusted life year

(QALY), of the surgical method Gastric Bypass as a treatment for obesity compared to not

performing Gastric bypass using a societal perspective.

1.3 Method

Costs, QALYs and probabilities of successful treatment were compared with no treatment to

calculate the cost-effectiveness. Data was obtained from the hospital in Värmland, Sweden

that performs Gastric bypass surgery on severely obese individuals and from literature studies.

4 A surgical method for the treatment of obesity. The aim is to reduce the volume of the stomach through silicone

band that is placed around the stomach(Parini &Nebiolo, 2004)

4

The definition of society in this study means the country of Sweden. The cost-effectiveness

analysis is often used in the evaluation of health policies (Boardman et al., 2010).

1.4 Limitations

This paper analyzes the cost effectiveness of Gastric bypass as a treatment for obesity

compared to no surgical treatment. It would have been preferable to compare Gastric bypass

to other surgical treatment methods as well. Gastric bypass was chosen due to that it is the

dominant surgical treatment for obesity and 97.5 percent of bariatric surgery in Sweden is

performed with Gastric bypass. It is also the only method of bariatric surgery performed in the

county council of Värmland. Data was obtained from the hospital in Torsby, Sweden, since it

is the only hospital in the county council of Värmlands that performs Gastric bypass on

severely obese. Individuals who receive Gastric bypass surgery are between the ages 18-60.

1.5 Disposition

The rest of the paper proceeds as follows; the theoretical framework is discussed in chapter 2,

containing an overview of the economic evaluation methods cost-benefit and cost-

effectiveness analysis. Relevant previous studies are discussed in chapter 3, whereas chapter 4

shows the model inputs. Results are shown in chapter 5 and chapter 6 contains the discussion

and conclusion.

5

2. Theoretical framework

2.1 Economic theory

When resources are scarce the allocation becomes of importance to achieve efficiency and to

maximize the benefits. A Pareto efficient allocation of resources is when no alternative

allocation can make at least one individual better off without making anyone else worse off

(Boardman et al., 2010). An inefficient allocation would then be when another alternative

allocation can be reached that makes at least one person better off without making anyone else

worse off. If an initial allocation (status quo) of resources is not Pareto efficient, movement

towards Pareto efficiency would be a Pareto improvement. According to Boardman et al

(2010) a much more feasible decision rule is the potential Pareto efficiency. It is based on the

Kaldor-Hicks criterion that a policy should be adopted if and only if those who will gain from

the policy could compensate those who will lose and still be better off. This means that

policies with positive net benefits are the only policies that should be adopted. With positive

net benefits the policy can become Pareto efficient by potential compensation to losers and

there will be only winners. The potential Pareto efficiency is also called the net benefit

criterion. Society will also maximize aggregate social wealth by always choosing policies

with positive net benefits.

Pareto efficiency is a basic concept for a cost-benefit analysis (CBA) and the potential Pareto

efficiency provides practical basis for conducting a CBA. CBA is a policy assessment method

and it considers all the consequences in monetary terms that the policy will give all the

members of society (Boardman et al., 2010). That is, the CBA takes into account the social

costs and the social benefits, and is therefore often referred to as the societal cost-benefit

analysis. The assessment method CBA can be applied on programs, treatments, projects,

regulations and other government policies. The purpose of CBA is to guide decisions making

so efficient allocation of the society´s resources is reached (Boardman et al., 2010). The value

of a policy in aggregate is measured as net social benefits (NSB) and is derived by taking the

social benefits (B) minus the social costs (C), NSB=B-C. The result from CBA can also be

expressed as the benefit divided by the cost, the benefit-cost ratio.

6

CBA requires the costs and benefits to be monetized. Measuring benefits in monetary units

can sometimes be impractical or even impossible. An alternative analytical approach is the

cost-effectiveness analysis (CEA) and is often used in the health care sector. It provides a

framework to help make choices between different policies (Brent, 2003). Boardman et al

(2010) describes three common constraints that can be avoided by using CEA. First the

analyst may be reluctant to monetize the most important impact of the policy this could be the

case when the analyst wants to predict number of saved lives but are unwilling to put that

impact in dollars. Second using CBA requires the analyst to monetize all impacts which can

be a burden. If an effectiveness measure does not capture all of the social benefits of each

alternative and some of these other social benefits are difficult to monetize using CBA may

prove difficult. The third constraint that CEA avoids is if the alternatives contain intermediate

goods whose linkage to preferences is not clear. CEA can then give the relative efficiency of

the alternatives.

Different public policies can be compared using CEA in terms of their costs and effectiveness

(Boardman et al., 2010). In CEA cost is measured in monetary units and as mentioned above,

CEA do not monetize benefits. Rather, benefits may be expressed in physical units such as the

number of avoided fatalities, or in some quality of life measure. Cost and effectiveness are

measured incrementally.

Consider a public policy that costs a certain amount of money if implemented. The effect of

the policy is the number of lives it saves. Implementing another public policy would also cost

a certain amount of money and can also save a number of lives. After the analyst has

identified the costs and effectiveness of the intervention the incremental cost-effectiveness

ratio (ICER) can be calculated. Taking the difference in cost between the two public policies

and dividing by the difference in the number of lives saved, the cost-effectiveness ratio

expresses cost per saved life. The ICER can be used as a basis for ranking different policies.

The most efficient of the policies would be the one that costs the least per saved life. The

evaluation of public policies using a CEA can be seen as an input for decision making

(Boardman et al., 2010).

Assuming two policies, labeled 1 and 2 the incremental cost-effectiveness ratio (ICER) of

policy 1 relative to policy 2 is CE1, 2 can be calculated as:

7

(1)

Where C is costs of the policies and E is the number of effectiveness units that the policies

give (Boardman et al., 2010). There are different types of costs used in the healthcare area;

direct cost, indirect costs and intangible cost (Drummond et al., 1997).

In health policies it may be possible to have an outcome measure that directly reflects the

change in individual´s health-related utility. The CEA is often referred to as cost-utility

analysis (CUA). CUA is useful when the analyst needs to make a trade-off between the

quality of life (morbidities) and the length of life (mortality) and is often used in health sector.

CUA is a form of CEA that uses a more complex measure of effectiveness that more directly

equivalent to changes in utilities. In CUA the incremental costs of alternative policies are

compared to the measurement of benefits or utility. A common measurement of utility in the

health care sector is quality-adjusted life years (QALY) (Boardman et al., 2010).

QALY combines quantity of additional years of life and the quality of life during those years

to give a standard unit for measuring health gain (Elliot & Payne, 2005; Boardman et al.,

2010). Using QALY to value states of health makes it possible to compare different

treatments (Elliot & Payne, 2005; Boardman et al., 2010).

The figure 1 below illustrates QALY with and without participating in a health programme

and the outcomes are assumed to occur with certainty. Additional years of life are measured

on the horizontal axis and the quality-adjusted life years weights are measured on the vertical

axis. For example, assume that an individual have a lower quality of life and a shortened

quantity of life due to a disease. Without the health programme the QALY weight is assumed

to be 0.5 and the individual is assumed to live an additional 10 years if having this health

related quality of life weight. The QALYs of the individual is then calculated as 0.5*10=5.

With the health programme the individual will increased the quality-adjusted life year weight

to 0.7 and live an additional 12 years, longer than without the health programme. The QALYs

of the individual has increased from 5 to (0.7*12=) 8.4. The area between without health

8

programme and with health programme is the quality-adjusted life years gained from the

health programme (Drummond et al, 1997).

Figure 1 the concept of quality-adjusted life years (QALY)

The weight of the QALY is measured on a scale of 0 (dead) to 1 (perfect health), that is, a

higher the number of the QALY-weight means a higher health-related quality of life

(Drummond et al., 1997).

According to Boardman et al (2010), these weights can be assessed using four approaches,

three direct methods and one indirect method.

The first method is (1) the health rating method (HR) in which the researchers derive the

health rating from interviews or questionnaires. Respondents are asked to locate their health

state on a scale between two endpoints, usually with a range between 0, meaning death and 1,

meaning perfect health. Due to the difficulty for respondents to assign numerical values to

different health states, an alternative version of the health rating method can be used. In this

version the respondents are asked to find their health state situated between endpoints on a

visual display. This point falls midway between initial placed health state and the upper and

lower endpoints.

Health-related quality of life

Perfect health 1

Dead 0 Years

0.5

0.7

10 12

Without programme

With programme

Quality-adjusted life years

gained

9

Constructing the weights of the QALY can also be done by (2) the time trade-off method

(TTO). In this method the respondents are asked to choose between different combinations of

length and quality of life. Often is the comparison between living a period of time with a

certain health related quality or live a shorter period of time with a better health related

quality (Boardman et al., 2010; Drummond et al., 1997).

In (3) the standard gamble method (SG) the respondents are asked to make a choice between

two alternatives presented in a decision tree. Assume that alternative A is an operation with

two possible outcomes, success or failure. If successful the individual would return to normal

health for a number of additional years. Successful surgery occurs to a probability of p.

Immediate death due to surgery occurs with probability of 1-p. The other alternative,

alternative B will guarantee that the individual lives a number of additional years with a

defined level of health impairment. The probability p is varied until the individual is

indifferent between alternative A and B. The p where the individual is indifferent between the

alternatives can be seen as the individual´s utility from alternative B when using a rating from

0 (death) to 1 (normal health). Individuals are assumed to act according to expected utility

hypothesis in the standard gamble method (Boardman et al., 2010; Drummond et al., 1997). A

direct comparison of the time trade-off method and the standard gamble method provide

similar utilities in terms of ordinal raking (Boardman et al., 2010).

Further Boardman et al (2010) describes the indirect method for deriving the weight of

QALY´s, using population surveys. Examples of these surveys are EQ-5D, Short form health

survey (SF-36) and the health utility index (HUI). The answers to the questions can be

transformed into to a certain QALY-weight using the TTO or the SG method.

The following formula show the incremental cost-effectiveness ratio (ICER) of policy 1

relative to policy 2, using QALY as an effectiveness measure. Consider two policies, labeled

1 and 2, both costs and QALY has been calculated for these two policies.

(2)

Result show the difference in costs between policy 1 and 2, divided by the difference in

QALY between policy 1 and 2 (Boardman et al., 2010).

10

The calculated ICER can be used an input in making decisions whether to implement a

treatment or not. In a situation where there are more alternative treatments the ICER is used to

evaluate the treatments against each other. The one with the lowest cost per QALY is the most

cost-effective if the purpose is to maximize health given a fixed budget. If only one treatment

is being evaluated the ICER of the treatment can be compared to a threshold value of a

QALY. This threshold value can be seen as the maximum willingness to pay for the

treatment. The maximum willingness to pay for a quality-adjusted life year is often mentioned

to be 500 000 SEK (Lundin, 2004). According to Socialstyrelsen (2010) can cost per QALY

be divided into four categories or classified as not being able to make an assessment. Table 1

below shows the four categories.

Cost per Quality-adjusted life years

Low Below 100 000SEK per QALY

Moderate 100 000-499 999 SEK per QALY

High 500 000-1 000 000 SEK per QALY

Very high Above 1 000 000 SEK per QALY

Not able to make assessment There is evidence that the policy has no effect or

the effect of the policy cannot be assessed.

Estimation or calculation is not relevant,

reasonable or possible.

Table 1 Cost per Quality-adjusted life years (QALY)

11

3. Previous studies

A number of previous studies have evaluated the cost-effectiveness of bariatric surgeries. In

this study five of them are reviewed.

Faria et al (2013) examined if Gastric bypass is a cost saving procedure. The study developed

a Markov model5 for three strategies; medical treatment, Gastric banding and Gastric bypass.

The medical treatment includes pharmacological treatment. The costs of the cost-effectiveness

analysis were calculated on lifetime basis and the study used a societal perspective. The study

included the cost of surgery and its associated risks of complications or death in relation to the

effectiveness in terms of weight loss and control of associated diseases. The surgical methods

were compared to the medical treatment. The population consisted of severely obese patients.

Subgroup analyzes was performed on patients without obesity related diseases, patients with

type-II diabetes, varying age and BMI. Faria et al (2013) found Gastric bypass to be a

dominant strategy with significant decrease in lifetime costs and increase in quality-adjusted

life-years (QALY). Gastric bypass gave higher QALY and saved on average more compared

to the medical treatment in a population of patients with BMI over 35. In terms of cost-

effectiveness the most beneficial were younger patients, patients without obesity related

diseases, and patients with BMI between 40 and 50. Gastric bypass is concluded from the

study to save resources in the health sector and increase QALY for obese individuals.

Padwal et al (2011) examined bariatric surgery compared to non-surgical treatment of obesity

and made comparisons between different methods of surgeries. Bariatric surgery was

examined both in clinical matter, its effectiveness and safety using randomized controlled

trials, and economically. In the clinical review adults and adolescents (the ages 11 to 17) who

met the criteria for surgery were included. Outcomes of surgery included were changes in

weight, quality of life, mortality and obesity related diseases, the length of stay in hospital and

re-operations. Comparing different surgical methods of bariatric surgery Padwal et al (2011)

found that bariatric surgery resulted in sustained weight reduction and to be more costs-

effective than non-surgical treatment. Gastric bypass surgery on patients with type II diabetes

and a mean BMI of 37kg/m2 increased the QALYs and saved costs compared to non-surgical

5Markov model is a method capable of modelling chronic disease states since it reflects the changes in and out of

health states referred to as a random process. The health states are random since there is unknown when they will

occur in the disease progress (Elliot & Payne, 2005).

12

treatment. The lack of precise and long term data makes a conclusion on mortality and

diseases related to obesity difficult. The method Gastric bypass was found to reduce weight to

a higher extent, having less operating times and less frequent re-operations than the surgical

method Gastric banding.

The objective of the study by Campbell et al (2010) was to assess the cost-effectiveness of

Gastric bypass and Gastric banding compared to receiving help with lifestyle modification

and pharmacological treatment. A Markov model was constructed to simulate weight loss,

health consequences and costs of surgical treatment. The model was used to estimate cost-

effectiveness ratios in terms of QALYs gained. The initial treatments were Gastric bypass or

Gastric banding, or no surgical treatment. Health status was divided into different states

related to the BMI of the patient; not obese BMI <30kg/m2; obese BMI 30-34.9 kg/m

2;

morbidly obese I BMI 35-39.9kg/m2; morbidly obese II BMI 40-49.9kg/m

2; super obese BMI

50kg/m2. The sixth health state was death. After receiving either Gastric bypass or Gastric

banding or no surgical treatment the patients entered one of the health states. The differences

between the states were treatment specific costs and expenditures, mortality risk and health-

related quality of life. In the study Gastric banding and Gastric bypass improved the patients’

health outcome although to a higher cost compared to no surgical treatment. Neither one of

the surgical methods were cost-saving compared to no surgical treatment, however they were

more beneficial in terms of QALY´s gained compared to no surgical treatment. Bariatric

surgery was most cost-effective for females and for patients who had higher initial BMI.

The objective of the study by Salem et al (2008) was to evaluate the incremental cost-

effectiveness ratio (ICER) of Gastric bypass and Gastric banding compared to no surgical

weight loss treatment and to each other. The method used was a deterministic decision model

from the health care perspective and lifetime expected costs and outcomes were compared.

Survival, health related quality of life and weight loss were the major endpoints. The lifetime

medical costs and the expectancy of life were calculated across sex, age and BMI.

Complications due to surgery were not included in the study for the reason that such

complications are not likely to have long-term impact on quality of life. Instead complications

were included into usual medical care cost of surgery. The base case was men and women in

different age categories the ages 35, 45 and 55 with a BMI of 40, 50 and 60. Gastric bypass

13

and Gastric banding was found to be cost-effective when examining the full range of BMI.

Gastric banding was more cost-effective than Gastric bypass for all base case scenarios. The

main factors influencing the cost-effectiveness of Gastric bypass and Gastric banding were

postoperative diseases and the extent of weight loss.

A previous study by Craig & Tseng (2002) estimated the cost effectiveness of Gastric bypass

as treatment of severe obesity compared to the alternative no treatment. The costs and the

effectiveness in terms of QALYs were discounted over the patient’s lifetime. The target group

of the study was both men and women in the ages 35 to 55 having a BMI between 40 and

50kg/m2. These individuals did not suffer from cardiovascular disease or any major

psychological disorder. The study only included individuals who had been unsuccessful with

maintaining a clinically meaningful weight loss despite many attempts (e.g., dieting, exercise,

behavior and pharmacological therapy). The individuals were also divided into subgroups of

risk; age, sex and initial BMI, to assess variation. The study used a deterministic decision

model for comparing the lifetime expected costs and outcomes. Both the costs and the QALY

were discounted with a rate of three percent, reflecting that events in future are to be less

valuable than costs and benefits occurring now. The estimated base case parameters were

derived from literature and discussion with experts. When estimates and model attributes were

unclear values were chosen in favor of no treatment. The subgroups of risk represented the

upper and lower bound of the cost-effectiveness ratios and these variations suggested that

Gastric bypass is more cost-effective among women and among those with high initial BMI.

However, the reduction in lifetime medical care costs was not greater than the cost of

treatment in any of the subgroup of risks, thus the analysis did not show Gastric bypass to be

cost saving from the societal perspective.

Table 2 below show the conclusions of previous studies. The previous studies agree upon

bariatric surgery being cost-effective and resulting in improved health. However, there is

disagreement considering the costs. Faria et al (2013) found Gastric bypass to be cost-saving

and dominant strategy. The other studies found bariatric surgery to be cost-effective at a

higher cost compared with no treatment.

14

Conclusion

Faria et al (2013) Gastric bypass was dominant strategy with significant decrease in lifetime

costs and increase in quality-adjusted life-years (QALY). GBP gave higher

QALY and saved more compared to best medical treatment.

Padwal et al (2011) Bariatric surgery resulted in sustained weight reduction and to be more costs-

effectiveness than non-surgical treatment GBP reduced weight to a higher

extent, having less operating times and less frequent reoperations than GB.

Campbell et al

(2010)

GB and GBP improved health outcome, gave considerable weight loss, at a

higher cost compared with no treatment. Most cost-effective for females and

for patients who had higher initial BMI.

Salem et al (2008) GBP and GB were cost-effective. ICER for GB was lower than GBP.

Craig & Tseng

(2002)

GBP was more cost-effective among women and those with high initial BMI.

The analysis did not show Gastric bypass to be cost saving from the payer

perspective.

Table 2 Result and conclusion of previous studies

Comments: GBP: Gastric bypass, GB: Gastric banding, QALY: Quality-adjusted life years. ICER: Incremental

cost-effectiveness ratio.

15

4. Model inputs

A decision-tree is useful when performing an economic evaluation and can be thought of as a

sequential or extended form of game against nature (Boardman et al., 2010). It is common to

use the technique of decision analysis for economic evaluation in the health care sector

(Drummond et al., 1997).

The decision analysis model can be illustrated as a decision tree that connects the initial

decision (the trunk) to the final outcomes (the branches) (Boardman et al., 2010). The

advantages of illustrating a decision tree are that it simplifies reality and the analyst can

quickly identify the data components (the probabilities, costs and utilities) needed to conduct

the analysis (Drummond et al., 1997). A decision tree should be read from the left to the right

to follow the sequences of decisions and the selection of contingencies. The sequence of

decision is denoted with a box, the random selections of contingencies are denoted with

circles and the outcomes or the endpoints are denoted with a triangle (Elliot & Payne, 2005).

The tree begins with a decision node, the box labeled 0 in the left thereafter the paths splits up

into two. The upper path represents the decision of implementation of the policy and the

lower path represents the decision not to implement the policy (Boardman et al., 2010). The

different paths represent forecasts of a policy for a number of individuals. These forecasts are

based on probabilities of frequencies for an event occurring in a population. In a CEA the

endpoints or the outcomes are associated with utilities in terms of QALY and costs. Dividing

cost with QALY cost per unit of effect is derived and comparison between different strategies

can be done (Drummond et al., 1997).

Figure 2 shows a decision tree comparing costs and outcomes between Gastric bypass and no Gastric bypass.

Comments: GBP: Gastric bypass surgery. No GBP: No Gastric bypass surgery.

Consultation

with the

doctor

GBP

No

GBP

Re-operation

Success

Lifetime with

initial BMI

0

Death

Death

Success

16

Figure 2 illustrates a decision tree for this study. First the individual has a consultation with

the doctor about the alternatives to receive Gastric bypass surgery or not to receive Gastric

bypass surgery. The two alternatives are represented by the upper and the lower paths,

respectively, leading away from the decision node.

The first chance node for the upper alternative, receiving Gastric bypass, show the possible

events. During the year 2011 the average age of an individual who received Gastric bypass

was 42 years. This is assumed to be the age when the individual has the chance to choose

between a Gastric bypass surgery or not. If the individuals decide to undergo Gastric bypass

surgery there is always a risk of death associated with the surgery, then the individual will not

become older than 42 years. Due to complications the individuals who survived initial surgery

might need re-operation within a year. The individuals might have a successful surgery

meaning the individual does not need re-operation and did not die. The probability of death,

re-operation and successful surgery must sum up to 1, meaning that if the patient receives

Gastric bypass one of these events will occur. The outcome of successful surgery, when

Gastric bypass has been chosen, is associated with costs and a number of QALYs.

The second chance node shows the possible events with probabilities of dying due to the re-

operation Pr (dead) and having a successful surgery Pr (success).

If no Gastric bypass was chosen it is assumed the patient will have a lifetime with initial BMI

in this case a BMI of 39.5kg/m2. This alternative is associated with medical costs for the

treatment of morbidities related to obesity and utility in terms of QALYs.

Using the probabilities the expected outcomes and the expected utilities are calculated,

generating the ICER for the base case in this study.

4.1 Data

4.1.1. Probabilities

The probabilities of postoperative death and re-operation are based on previous studies. 2.2

percent of the patients had postoperative complications serious enough to require re-operation

(Sjöström et al., 2004). The probability of postoperative death is estimated by Sjöström et al

(2004) and is assumed to be 0.25 percent. Successful surgery is assumed when the patient

survived and did not have to go through re-operation.

17

Variable Probability Reference

Death 0.0025 Sjöström et al (2004)

Re-operation 0.0220 Sjöström et al (2004)

Successful surgery given re-operation 0.021946 Own calculations based on

Sjöström et al. (2004)

Death given re-operation 0.000055 Own calculations based on

Sjöström et al. (2004)

Successful surgery 0.9755 Own calculations based on

Sjöström et al. (2004)

Table 3 probabilities of each event when Gastric bypass is chosen

4.1.2 Costs

All the costs in this study are expressed in Swedish crowns. The costs included in this study

are costs associated with initial surgery and re-operation, costs for follow-ups and obesity

related diseases, supplements, costs of sick leave and disability pension. The costs data was

received from the county council of Värmland and obtained from previous studies and

literature. The costs are expressed 2011 years prices. The cost of initial Gastric bypass

surgery, follow-up after surgery, re-operation and cost of death will only occur one time and

are not discounted. The costs of obesity related diseases, supplements, costs of sick leave and

disability pension are expected to occur over the remaining years of life. These costs are

discounted to present value (the year 2011) with a social discount rate of three percent.

During the year 2011 the number of individuals who had Gastric bypass surgery in the

hospital in Torsby was 258, of these 63 were men and 195 women. The average age was

about 42 years and average BMI was 39.5 (Landstinget i Värmland, 2013). This is assumed to

be the age and BMI when the individual has the chance to choose between a Gastric bypass

surgery or not. The remaining life expectancy of a normal weighted individual at the age 42 is

about 39 years for men and 42 years for women (SCB, 2012).

The initial cost of Gastric bypass surgery is 60 000 SEK in 20116. According to the NIOK

(2009) study a reasonable estimate of the average follow-up costs after surgery for the first

6 The amount is based on a DRG (Diagnosis Related Groups)-price-list with code 288 in 2011 years prices.

18

year is 10 000 SEK. The cost of re-operation due to syndromes after surgical procedures on

the stomach is 51 992 (SKL, 2011). Compensation for death in healthcare is paid if the

damage caused by the care and could have been avoided. The compensation is approximately

45 000 SEK (Patientförsäkringen, 2013).

The cost items; diabetes type II and cardiovascular disease accounts for more than 80 percent

of total health care costs that overweight and obese individuals cause the healthcare (Persson

et al., 2004). For these diseases there are also reliable data available.

During the year 2011 20 individuals, who received Gastric bypass, developed Type II diabetes

(Landstinget i Värmland, 2013). In previous studies was the prevalence of diabetes type II 10-

28 percent (NIOK, 2009). In this study the prevalence of diabetes is assumed to be 10 percent.

According to Demissie et al (2012) 63 percent of individuals with diabetes had complete

withdrawal of treatment after Gastric bypass surgery. For the alternative receive Gastric

bypass the prevalence of diabetes is assumed to be 3.7 percent. For No gastric bypass the

prevalence of diabetes is assumed to be 10 percent.

A previous study found that among men and women with a BMI>40 14 percent and 19

percent, respectively, had cardiovascular disease (NIOK, 2009). In a previous study patients

operated with the Gastric bypass found the risk of developing cardiovascular disease

decreased by 39 percent among men and 25 percent among women (NIOK, 2009). In this

study it is assumed that the prevalence of cardiovascular disease is 14 percent for men and 19

percent for women. For the alternative receive Gastric bypass the prevalence of

cardiovascular disease among men is assumed to be 8.5 percent. For women in the same

alternative, the prevalence of cardiovascular disease is assumed to be 14.3 percent. For No

gastric bypass the prevalence of cardiovascular disease is assumed to be 14 percent for men

and 19 percent for women.

The cost of sick leave and disability pension is derived from the study by Narbro et al (1999).

The study found the number of days in average of sick leave and disability pension the year

before Gastric bypass surgery similar in both the control group and in the group who received

gastric bypass surgery. After surgery the average numbers of days were 107 and 10 percent

19

lower in the surgical group compared to the control group. The cost data is received from

SCB (2011) and calculation is done with average wage per month in all sectors for men and

women. The number of workdays is assumed to be 224 per year.

Table 4 presents an overview of the costs per patient and year. The price of the obesity related

diseases and cost of sick leave and disability pension per patient are the same for the both

alternatives, Gastric bypass and No Gastric bypass. However, the prevalence of obesity

related diseases of the two alternatives differ from each other. The prevalence of obesity

related diseases are higher among individuals who have not received Gastric bypass (This is

presented in Table 5). The obesity related diseases are expressed per patient for one year.

Costs items SEK Cost per patient

Men Women

Initial GBP surgery 60 000 60 000

Follow-ups 10 393 10 393

Re-operation7 51 992 51 992

Death8 44 603 44 603

Type-2 Diabetes per year 42 626 37 005

Cardiovascular disease9 per year 128 603 165 466

Sick leave and disability pension per year 178 963 153 725

Supplements10

2 021 2 021

Table 4 shows the cost per patient and year. The cost items are expressed in 2011 years prices.

Table 5 shows the costs of the alternatives Gastric bypass and not receiving Gastric bypass.

Note that the 258 individuals who received Gastric bypass are compared to the case if 258

7Leakage in the joint between the stomach pouch and the small intestine called Anastomosis leakage

(Läkemedelskommittén i Värmland, 2011). 8The most common causes of early postoperative death due to bariatric surgery are pulmonary embolism, cardiac

events and intestinal leaks with sepsis (Omalu et al., 2007). 9Includes the conditions hypertension, heart attack and angina.

10 Refers to as supplements of multivitamins, iron supplements, calcium supplements and supplements of

vitamin B12.

20

individuals were not to have Gastric bypass surgery. The costs are calculated as follows, the

cost of initial Gastric bypass surgery per patient is 60 000. This cost is multiplied with the

total number of men (63 individuals) receiving Gastric bypass surgery and equals 3 780 000

SEK11

. All the cost items are calculated as the prevalence of individuals having the cost

multiplied with the price of the cost item. The prevalence in percent of diabetes type II and

cardiovascular disease for men and women and each alternative are denoted with parentheses.

The cost of death is also associated with the cost of production loss and is calculated on the

average wage per year for men and women in all sectors until the age 65.

Costs items SEK Gastric Bypass No Gastric Bypass

Men Women Men Women

Initial GBP surgery 3 780 000 11 700 000 - -

Follow-ups 654 759 2 026 635 - -

Re-operation 72 061 223 046 - -

Death 7025 21 744

Type-2 Diabetes 99 361(3.7) 266 991(3.7) 268 544(10.0) 721 598(10.0)

Cardiovascular

disease

442 271(8.5) 1 532 629(14.3) 1 134 278(14.0) 6 130 515(19.0)

Sick leave and

disability pension

10 142 496 26 966 160 11 274 669 29 976 375

Supplements 127 323 394 095 - -

Table 5 shows the costs of the alternatives Gastric bypass and not receiving Gastric bypass applied on 258 individuals,

expressed in 2011 years prices. Comments: GBP: Gastric bypass surgery. (%): Prevalence of disease in the

alternatives.

4.1.3 Quality-adjusted life years (QALYs)

QALY weights range from 0 meaning death to 1 meaning perfect health (Drummond et al.,

1997). Craig & Tseng (2002) estimated quality of life and found a negative relationship

between health-related quality of life and BMI.

In previous studies the QALY-weights of individuals with BMI of 40 kg/m2

or more in the age

40 was 0.82 for men and 0.73 women (McEwen et al., 2010). After bariatric surgery the

11

All calculations are shown in APPENDIX.

21

QALY-weights were 0.90 for men and 0.88 for women. The remaining life expectancy of a

normal weighted individual at the age 42 is about 39 years for men and 42 years for women

(SCB, 2012). Individuals who are severely obese and suffer from obesity related morbidities

have shorter life expectancy compared to an average individual of that age. Whitlock et al

(2009) found life expectancy to be shortened by 10 years for severely obese individuals with a

BMI of 40. The study was performed on individuals from Europe and the United states and

will be used as an assumption in this study. A previous study by Pope et al (2006) found an

additional 2.6 years of life expectancy with Gastric bypass surgery.

The QALY-weight of an individual receiving Gastric bypass surgery and have to go through

re-operation is assumed to be the same as for successful surgery since a decrease of QALY

would most likely only occur within the first year after initial surgery.

Table 6 shows the different QALY-weights of men and women of the two alternatives Gastric

bypass and No Gastric bypass, re-operation and death.

QALY-weights and life expectancy Men Women Reference

QALY-weight successful GBP

0.90 0.88 McEwen et al (2010)

QALY-weight No GBP

0.82 0.73 McEwen et al (2010)

QALY-weight re-operation 0.90 0.88 McEwen et al (2010)

QALY-weight of death 0 0 Own assumption based on

(Drummond et al., 1997)

Life expectancy GBP 72 75 Own calculation based on

(SCB, 2012)

Life expectancy No GBP 75 78 Own calculation based on

(SCB, 2012)

Table 6 show the health related Quality of life weights with and without Gastric bypass for men and women

Comments: GBP: Gastric bypass surgery. No GBP: No Gastric bypass surgery.

4.2 Sensitivity analysis

The prediction of costs and effects in policy evaluation are rarely done with great certainty

(Boardman et al., 2010). For this reason the result from the base case is tested with a

sensitivity analysis. The sensitivity analysis is done in three steps; first the uncertain

parameters must be identified. Second, a plausible range for which the uncertain parameters

22

can vary is specified. And last, costs and effects are simulated with a number of draws based

on the defined parameter ranges (Drummond et al., 1997). The parameters are assumed to

have a uniform distribution. The costs data, the effects and the probabilities were obtained

from previous studies and an experiment was conducted on them. All the variables contain

uncertainty.

The sensitivity maximum of the costs is assumed to be plus 5 percent and the sensitivity

minimum is assumed to be minus 5 percent of the base case.

The quality-adjusted lifetime weights are different for men and women. Receiving No Gastric

bypass QALY-weight of men would be 0.82 and 0.73. For an individual receiving Gastric

bypass the QALY-weight is 0.90 for men and 0.88 for women. The QALY-weight of re-

operation is assumed to be the same as for successful surgery since a decrease of QALY

would most likely only occur within the first year after initial surgery. There is a chance of

dying after a surgery and the QALY-weight of death is assumed to be 0 since death would

occur directly after the surgery. For the QALY-weights a range between plus and minus 0.1

QALY is chosen except for the QALY-weight of death where 0 QALY is assumed.

The probability for the base case of successful surgery is 0.9755 and the probability of re-

operation is 0.0220. A previous study determined the probability of postoperative death to be

quite low and is 0.0025. The probability of success given re-operation is 0.021946 and the

probability of death given re-operation is 0.000055. For the probabilities of re-operation,

death and successful surgery a range between plus and minus 2 percent is chosen.

23

Table 7 provides an overview of the base case variables and the minimum and maximum

ranges in the sensitivity analysis.

Variable Base case Sensitivity

minimum

Sensitivity

maximum

Cost of No GBP 1 043 654 846 991 472 104 1 095 837 588

Cost of successful GBP 905 131 607 859 875 027 950 388 187

Cost of re-operation-success GBP 905 426 692 860 155 357 950 698 027

Cost of re-operation-death GBP 1 527 717 487 1 451 331 613 1 604 103 361

Cost of death GBP 1 521 878 218 1 445 784 307 1 597 972 129

QALY-weight No GBP 32 29 35

QALY-weight GBP success 39 35 43

QALY-weight GBP re-operation 39 35 43

QALY-weight death GBP 0 0 0

Probability successful GBP 0.975500 0.955990 0.995010

Probability re-operation GBP 0.022000 0.021560 0.022440

Probability re-operation-success GBP 0.021946 0.021510 0.022380

Probability re-operation-death GBP 0.000055 0.0000054 0.0000056

Probability of death GBP 0.002500 0.002450 0.002550

Table 7 variables for the base case and sensitivity analysis applied on 258 men and women. Comments: No GBP:

No Gastric bypass surgery. GBP: Gastric bypass surgery.

24

5. Result

The expected costs and QALY´s of the individuals for the base case were calculated using the

cost items and probabilities. Applied on the data with the 258 individuals, the costs of the

alternative receiving Gastric bypass sum up in total to 902.7 million SEK and includes the

lifetime cost of obesity related diseases, cost of successful surgery, the two outcomes of re-

operation and the cost of postoperative death. The expected QALYs of receiving Gastric

bypass also include QALYs of successful surgery, re-operation and postoperative death and

are 39. The sum of the cost for the other alternative, not receiving Gastric bypass, sum up to

1,043.7 million SEK. The expected QALYs of not receiving Gastric bypass are 32. Table 8

shows the cost and effects of the treatment and no-treatment alternative.

Cost Effectiveness

Gastric bypass 902 714 191 39 QALYs

Not receiving Gastric bypass 1 043 654 846 32 QALYs

Table 8 cost and effectiveness of the base case

The ICER show the cost per QALY gained for all individuals and is the differences in cost

between the two alternatives divided by the difference in QALY´s. The cost of Gastric bypass

is lower than the cost of no Gastric bypass and the QALY of Gastric bypass is more than no

Gastric bypass. In this study the cost per QALY gained, is -19 562 951 SEK

(3)

The result from a simulation of 5000 cases within the maximum and minimum ranges in table

7 is shown in figure 3 below. The difference in QALYs between Gastric bypass and no

Gastric bypass is shown on the horizontal axis. The QALYs of Gastric bypass are more than

no Gastric bypass in 98.78 percent of the cases. The difference in costs between Gastric

bypass and not receiving Gastric bypass is shown on the vertical axis. The QALYs of Gastric

25

bypass are larger than no Gastric bypass and the cost of Gastric bypass is lower than no

Gastric bypass leading to all the values from the simulation lying on the south east quadrant in

the diagram.

Figure 3 shows the result from the simulation with 5000 ICER

Using the information from table 1, in chapter 2 where the cost per QALY is considered to be

moderate if it is under 500 000 SEK. The cost per QALY over this amount would be

considered not cost-effective. The incremental cost-effectiveness ratios, the dots in the

diagram are all under this threshold value meaning that all values of the simulation resulted in

cost-effective values. All the cases of the simulation were even pure cost-saving, i.e. increased

effectiveness at a decreased cost. The result from this study indicates Gastric bypass to be a

dominant strategy with significant decrease in lifetime costs and improved health in terms of

QALYs.

26

6. Discussion and Conclusion

The incremental cost effectiveness ratio for the base case is – 19 562 951 SEK. This is the

incremental cost for one quality-adjusted life year and can be compared to the values in table

1. Incremental cost for one quality-adjusted life year between 100 000 to 499 999 SEK can be

seen as moderate costs (Socialstyrelsen, 2010) and the maximum willingness to pay (WTP)

for one quality-adjusted life year is sometimes argued to be 500 000 SEK (Lundin, 2004).

Given the assumptions made about the cost items in this study, the cost for the alternative

Gastric bypass are much lower than the cost of not receiving Gastric bypass. The simulation

of 5000 cases resulted in values far from the maximum WTP and all the cases were pure cost

saving. In the majority of the cases Gastric bypass improved health in terms of QALYs.

However, in 1.22 percent of the cases the QALYs were negative meaning that the QALYs of

Gastric bypass were less than no Gastric bypass. Due to that the cost-effectiveness analysis in

this study is based on a number of assumptions there will always be some degree of

uncertainty about the result.

Obstacles for not implementing a public policy might be that the costs are paid by a part in

society and benefits are received by another part this is not the case in this study. The county

council of Värmland bears the burden of the costs and will as more actors in society,

individuals and municipality receive cost-savings of implementing Gastric bypass.

Previous studies found evidence for bariatric surgery to be cost-effective, although not always

the Gastric bypass method. The result from this study indicates Gastric bypass to be a

dominant strategy with significant decrease in lifetime costs and improved health in terms of

QALYs. The same result was shown in one of the five previous studies, whereas most other

studies found Gastric bypass to have higher costs and improved QALYs, with a relatively low

cost per gained QALY. The result of Faria et al., (2013) is consistent with the result from this

study. Both Campbell et al., (2010) and Craig & Tseng (2002) found Gastric bypass to be

most cost-effective among women and individuals with higher initial BMI further studies on

this could be of interest. In this study sex-specific results were not analyzed.

The analysis has some limitations that should be mentioned. Due to the lack of detailed and

reliable data on all potential costs associated with overweight and obesity, some potential

costs might not be included in this study. For example, cost of cancer, infertility,

musculoskeletal disorder and psychosocial disorder may all be related to obesity, but is not

27

included in this study. An increase in health care cost from ageing is expected to occur for

individuals in both the Gastric bypass alternative and not receiving Gastric bypass. This is the

reason for not including increased health care cost from ageing in this study. Another

potential limitation is the assumption about having the same QALY-weight through life. The

argument could be that it should be decreasing. However it would make no difference if the

decrease is as much in the alternative Gastric bypass as in no Gastric bypass. The QALY-

weight of successful surgery and re-operation are assumed to be the same even though one

can assume those who have gone through re-operation would have a lower QALY-weight.

The reason for not taking this lower QALY-weight into account is that it is assumed to only

occur the first year after surgery. Furthermore, can the assumed probabilities for the different

outcomes; success, re-operation and death represent another weakness of the study. The

probabilities are assumed from literature and may not be completely accurate in the

perspective of Sweden and Värmland.

The increasing prevalence of obesity and the major pressure on the health care sector obesity

causes makes treatments an important topic. This study concludes that Gastric bypass surgery

as a treatment improves the quality of life measured in quality-adjusted life years in patients

with an average BMI of 40 kg/m2

and decreases the associated health care costs. This is when

estimation is done over the lifetime of the individuals. The treatment was found to improve

the quality of life and it seems to be consistent with previous studies. The decrease in the

associated health care costs found in this study is consistent with one of the previous studies

reviewed. The result from the cost-effectiveness analysis can be used as a guide for policy

makers whether to implement a treatment or not. Given the calculations in this study the

recommendation is to implement Gastric bypass as a treatment for severe obesity.

In this study the Gastric bypass method was compared to not receiving any surgical method.

Further research of interest on the subject may be to compare Gastric bypass to other surgical

treatment method.

28

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32

APPENDIX

The total number of men receiving Gastric bypass were 63 and the total number of women

195. Table 9 shows the calculation done for the base case with the total individuals receiving

Gastric bypass.

Costs items SEK Gastric Bypass

Men Women

Initial Gastric bypass

surgery

63*60000=3780000SEK 195*60000=11700000SEK

Follow-up 63*10 393=654759SEK 195*10393=2026635SEK

Re-operation 2.20% of 63=1.386

1.386*51992=72061SEK

2.20% of 195=4.29

4.29*51992=223046SEK

Death 0.25% of 63=0.1575

0.1575*44603=7025SEK

0.25% of 195=0.4875

0.4875*44603=21744SEK

Type-2 Diabetes 10% of 63=6.3

0.37*6.3=2.331

2.331*42626=99361SEK

10% of 195=19.5

0.37*19.5=7.215

7.215*37005=266991SEK

Cardiovascular disease 0.14*63=8.82

8.82*0.39=3.4398

3.4398*128603=442369SEK

0.19*195=37.05

37.05*0.25=9.2625

9.2625*165466=1532629SEK

Sick leave and disability

pension

63*160992=10 142 496SEK 195*138288=26 966 160SEK

Supplements 63*2021=127323SEK 195*2021=394 095SEK

Table 9 show the calculation of the cost items in the base case in SEK for the alternative Gastric bypass

Table 10 shows the calculations of the cost items in the base case with the total individuals for

the alternative No Gastric bypass.

33

Costs items SEK No Gastric Bypass

Men Women

Type-2 Diabetes 6.3*42626=268544SEK 19.5*37005=721598SEK

Cardiovascular disease 8.82*128603=1134278SEK 37.05*165466=6130515SEK

Sick leave and disability pension 63*178963=11 274 669SEK 195*153725=29 976 375SEK

Table 10 show the calculation of the cost items in the base case in SEK for the alternative No Gastric bypass