Archives of Medical Research 31 (2000) 223–227

0188-4409/00 $–see front matter. Copyright © 2000 IMSS. Published by Elsevier Science Inc.PII S0188-4409(00)00048-5

ORIGINAL ARTICLE

Impact of Physical Functioning of Health Status on Hospitalizations,Physician Visits, and Costs in Diabetic Patients

Maribel Salas,*

,

** Tom Bubolz*** and Jaime J. Caro*

,

***

*Dartmouth Medical College, Hanover, NH, USA**McGill University, Montreal, Quebec, Canada

***Caro Research, Concord, MA, USA

Received for publication September 23, 1998; accepted November 19, 1999 (98/118).

Background.

The objective was to determine the impact of the physical functioning of di-abetic patients on hospitalizations, physician visits, and costs using Medicare data.

Methods.

A total of 12,863 people who completed the interview of the 1993 MedicareCurrent Beneficiary Survey (MCBS) was studied. A diabetic patient was defined as a pa-tient who answered this question positively: Are you diabetic? The final sample was madeup of 10,517 non-diabetic patients and 2,003 diabetic patients. The Activity Daily Living(ADL) Scale of the MCBS was used to assess physical functioning. Hospitalizations, phy-sician visits, and costs were obtained from the Medicare database.

Results.

We found that diabetic patients had a worse perception of physical functioningthan non-diabetic patients (ADL disability score 8.47

6

15 vs. 5.8

6

13). Patients with di-abetes consume more resources and the costs associated with their medical care are higherthan for non-diabetic patients (mean total reimbursement in 1993 for diabetics was 6,847

6

15,071 USD vs. 3,773

6

9,971 USD). Total costs were highly correlated with the ADLdisability score (

r

5

0.75).

Conclusion.

Self-perception is highly correlated with the care cost of patients withdiabetes. © 2000 IMSS. Published by Elsevier Science Inc.

Key Words:

Health, Physical, Cost, Diabetes, Hospitalization, Medicare.

Introduction

Clinical status, functioning, and well-being determine howpeople perceive their health (1). The patient’s perspectivecan be decisive in choosing when to seek help, the degree ofcompliance with treatment, and whether or not to changeone’s lifestyle. Studies of the effect of medical treatmentsnow routinely include protocols for asking the patientsthemselves questions about their health and well-being.Self-perception of patients concerning their health status de-termines their need and this need pushes these patients toenter the health care system (2). According to Fowler, theemphasis on patient reports to assess medical results repre-sents an evolution in research methods as part of a generalimprovement in the quality of outcome studies (3).

Self-perception of health status, particularly physicalfunctioning, could be key in patients with chronic diseasesbecause these patients require treatment for long periods oftime and their self-image could be modified by the disease.

Diabetes mellitus is the most common of the serious met-abolic diseases with a 1% overall prevalence in Western so-cieties. In the U.S., it is a major health problem, with morethan 6 million diabetic Americans and the incidence rate isincreasing at around 6% per year (4). It is the third most fre-quent cause of death in the U.S. The death rate is higher forminorities; for example, the age-adjusted death rate forwhites is 14.1 compared with 26.0 for all other races (5). Di-rect medical costs of diabetes to the U.S. are estimated at7.4 billion USD per year and if indirect costs are included,the costs increase to 20.4 billion USD (6).

One of the main problems in the control of patients withdiabetes is the acceptance that they have a chronic diseaserequiring a change in lifestyle. Generally, patients with dia-betes are not aware that they are vulnerable to late compli-

Address reprint requests to: Jaime Caro, 336 Baker Avenue, Con-cord, MA 01742 USA. Tel.: (

1

508) 371-1660; FAX: (

1

508) 371-2445;E-mail: jcaro@caroresearch.com

224

Salas et al./ Archives of Medical Research 31 (2000) 223–227

cations and that life expectancy is shortened. The primaryreaction may be denial with an accompanying refusal to co-operate. At the other extreme is excessive preoccupationwith the illness.

While numerous studies have addressed the relationshipof chronic diseases with health outcomes (7,8), we stillknow little about the impact of self-perception of health sta-tus in patients with diabetes on hospitalizations, physicianvisits and costs.

Methods

Medicare Program.

Medicare is a health insurance pro-gram that was established in the U.S. in 1965 to provide allelderly people with ready access to treatment for acute ill-ness (9). Almost all diabetic patients who are

.

65 years ofage have health-care coverage, but 13.5% of those who are18–64 years of age have no health insurance. Government-funded insurance mechanisms cover approximately 57.4%of adults with diabetes, including 26.4% of patients 18–64years of age and 96% of those older than 65 years of age,which indicates a significant societal burden associated withdiabetes (10); however, the success of Medicare is noted(10,11).

Medicare Current Beneficiary Survey (MCBS).

The MCBSis a continuous, multipurpose survey of a representativesample of the Medicare population conducted by the Officeof the Actuary, Health Care Financing Administration(HCFA), Washington, D.C. The central goals of this surveyare the following: to determine sources of payment for allservices used by Medicare beneficiaries, including copay-ments, deductibles, and non-covered services; to ascertainall types of health insurance coverage and relate coverage tosources of payment, and to trace processes over time, suchas changes in health status, spending down to Medicaid eli-gibility, and the impacts of program changes (12). Sampledbeneficiaries are interviewed in person three times a year.The first round of interviewing was conducted from Sep-tember through December 1991.

In this article, we report on the people who completedthe MCBS interview in 1993. Some data in the MCBS arenot requested in the interview because they can be obtainedfrom other Medicare claims files, such as diagnoses, proce-dures, and covered charges (12,13).

Sampling procedure.

The first stage of sampling was theselection of 107 geographic primary sampling units (PSUs),consisting of counties or groups of counties chosen to repre-sent the nation. PSUs are used in national surveys to reducecosts of traveling for interviews while maintaining nationalrepresentation. Within PSUs, the sample was restricted toaddresses within certain geographic subareas correspondingto postal ZIP codes. Beneficiaries residing in these areas

were selected for the sample by systematic random sam-pling within age strata. Two groups were not sampled: thedisabled and the most elderly of old persons. Given the sam-ple size of about 12,000 persons permitted by the budget, al-location-by-age allows for analyses by gender, region, andmetropolitan area (12).

Survey interview process.

This survey interviewed the sam-pled person directly, but if the person was unable to answerthe questions, he or she was asked to designate a proxy re-spondent, usually a family member or close acquaintancefamiliar with his or her care. In this study, 11% of commu-nity interviews were done by proxy. The interview processis divided in rounds three times yearly, where different dataare obtained by round. The information requested is relatedto the use of health services, medical care expenditures,health insurance coverage, sources of payment, health statusand functioning, and a variety of demographic and behav-ioral information such as income, assets, living arrange-ments, family support, and access to medical care. Data re-lated to health status is collected in the third round with arefusal of 1.6% of the initial sample. The community inter-view, which constitutes more than 90% of MCBS data, isconducted using a computerized questionnaire on a note-book-size personal computer. Data sent electronically by in-terviewers are received by microcomputers and analyzed.The total time required in the interview is 1 h. All interview-ers are trained and retrained, particularly in analyzing insur-ance statements, apportioning payments, and dealing withthe stresses of interviewing the chronically ill. For Hispanicpersons a Spanish translation is provided. MCBS interviewdata are linked to Medicare claims and other administrativedata to enhance their analytic power. The final file consistsof survey, administrative, and claims data. All personalidentifying information is removed (12–15) for confidenti-ality purposes.

Study population.

A total of 12,863 people who completedthe interview of the Medicare Current Beneficiary Surveyobtained in 1993 were studied. A diabetic patient was de-fined as a patient who answered the question positively: Areyou diabetic? The final sample was constituted of 10,517non-diabetic patients and 2,003 diabetic patients.

Physical functioning.

The Activity Daily Living (ADL)and the Instrumental Activity Daily Living (IADL) of theMCBS assessed physical functioning. The ADL is an instru-ment commonly used to evaluate physical functioning,mainly disability (16). It encompasses the following six ba-sic human functions: bathing; dressing; toileting; transfer;continence, and feeding. It provides an objective method ofclassifying heterogeneous groups of people with chronic ill-nesses (17,18). ADL assesses the basic capacity of personsto care for themselves while instrumental activities of dailyliving (IADL) assesses the ability to perform household

Salas et al. / Archives of Medical Research 31 (2000) 223–227

225

chores or go shopping (19). In our study, different questionswere grouped in order to obtain scores for each componentof physical functioning. In this survey, there were only twoquestions related to social functioning and general health.Therefore, we analyzed them separately.

The item internal consistency of Activities of Daily Liv-ing (ADLs) and the Instrumental Activities of Daily Living(IADLs) in the MCBS were evaluated by inspecting the cor-relation among items. In addition, each item was also evalu-ated in relation to its hypothesized scale. The inter-item cor-relation was 0.54 for the social functioning dimension andthe general health dimension. The reliability index for allitems of the MCBS was 0.98.

Results

Medicare beneficiary survey.

Of 12,540 interviewed peo-ple, 16% were diabetics, 0.01%, not ascertained, 0.12%, donot know, 0.02% refused to be interviewed, and the remain-der were not diabetics (10,517

5

83.85%). Table 1 showsthe demographic characteristics of diabetic vs. non-diabeticpatients. There were no statistical differences in age andgender. In relation to race, the prevalence of diabetes washigher in Hispanics than in whites. Fifty-two percent of dia-betic patients had fewer than 11 years of education com-pared to 42% of non-diabetic patients. With respect to in-come, 63% of diabetics earned less than 15,000 USD/year.

Table 2 shows some clinical characteristics of diabeticvs. non-diabetic patients. Both groups were obese, but thedegree of obesity was higher in the diabetic group. The most

frequent diseases in this sample were hypertension and ar-thritis, which contribute to increased costs. In relation toprocedures, diabetic patients received more surgeries sec-ondary to cataracts, while non-diabetics had more traumaticamputations.

Utilization data are presented in Table 3. It is evident thatdiabetic patients consume more resources and that costs asso-ciated with their medical care are higher than with non-diabet-ics. Sometimes the costs associated were almost 60% higherfor diabetics, particularly in relation to hospitalizations.

Table 4 shows the Watson classification for physicalfunctioning by diabetes. The percentage of patients who hadmore disabilities was the diabetic group. The ADL Disabil-ity Score was on average three points higher for diabetics.In relation to cost, the program spent more money on thetreatment of diabetics. In addition, costs, physician visits,and in-patient days were directly related to the patient’sself-perception of physical functioning.

Conclusions

The Medicare Current Beneficiary Survey (MCBS) origi-nated from the need to provide valid estimates of variouskinds of health care spending, such as long-term care spend-ing or expenditures of different age groups, to describe theeffects of the Medicare program to its beneficiaries and tomodel the effects of proposed program changes (12). We fo-cused on the section related to health status, particularlyphysical functioning. Measures of physical functioningcommonly include items related to limitations, disabilities,capacities, and abilities in bodily behaviors common to ev-eryday life (e.g., self-care, walking, running). These mea-sures make it possible to rank the overall functional statusof people in an ordered manner, to make comparisonsamong them as individuals or groups, and to detect changesover time (20). Some studies have shown adequate reliabil-ity and validity indexes for measures of ADL, IADL (17),

Table 1.

Demographic data of diabetic and non-diabetic patients

Diabetic patients(

n

5

2,003)Non-diabetic patients

(

n

5

10,517)

Female (%) 1,122 (56) 5,979 (57)Age (median

6

SD) 70

6

13 69

6

15Race (%)

White 79.0 86.5Hispanic 1.4 0.9Black 17 10.3Asian 0.5 0.4Others 2.1 1.9

Education (years) (%)None 2 4

,

8 33 269–12 47 46

.

12 18 24Income (USD/year) (%)

,

5,000 9 85,000–35,000 84 80

.

35,000 7 12Marital status (%)

Married 50 48Widowed 34 32Divorced 8 8Other 8 12

Table 2.

Clinical characteristics of diabetic and non-diabetic patients, Medicare. 1993

Diabetic patients(

n

5

2,003)

Non-diabeticpatients

(

n

5

10,517)

Current smoking habit (%) 14 16.7Median body mass index 37 29Comorbidities (%)

Hypertension (ICD-9, 401) 72 47Arthritis (ICD-9, 716) 61 51Arteriosclerosis (ICD-9, 440) 21 14Rheumatoid arthritis (ICD-9, 714) 20 12Asthma (ICD-9, 493) 16 14Angina pectoris (ICD-9, 413) 11 6Other 75 61

Procedures in these patients (%)Surgery for cataracts 20 17

226

Salas et al./ Archives of Medical Research 31 (2000) 223–227

and a combined ADL/IADL scale (21). In this study, we es-timate item internal consistency and item discriminant va-lidity in order to consider this survey as a reliable and validsource of information. A high index of reliability and valid-ity were found.

Previous results show that these measures of self-main-taining function can be used reliably in clinical evaluationsas well as in program evaluations and in planning (22). Infact, chronic diseases such as rheumatoid arthritis (23) andhypertension (24) frequently affect physical activities. In re-lation to diabetes, Johnson et al. (25) studied the health-related quality of life of 54 diabetic Pima Indians and foundthat age was significantly associated with four of the eightdimensions, and that diabetic patients with co-morbidities

had lower health status scores. There is a study that focuseson the African-American population, which had a worsehealth perception and lower quality of care (26). It has beenreported that diabetic patients are more than twice as likelyto be hospitalized as the population as a whole (27), and notonly minorities. In our study, we found that diabetic patientsare 76% more likely to be hospitalized than non-diabetic pa-tients. Additionally, average physician visits and hospital-izations were higher in patients; this increased proportion-ally with the disability score. A direct relationship betweenphysical functioning and consumption of resources of medi-cal care was found. In fact, diabetic patients consume moreresources and their medical care costs almost 60% morethan non-diabetic patients. Reasons for this consumption aremultiple and complex. It may be associated with co-morbid-ities, more frequent in these patients, disease evolution, poorcompliance with diet, and pharmacological treatment, etc. Theproblem with the diabetic population is that they need to beaware that the goal is to live with diabetes, not for it (28).

The MCBS provides us with reliable information con-cerning physical functioning, but if someone is interested instudying health status, it would be necessary to includeother dimensions. In the MCBS, there were only two ques-tions unrelated to physical functioning, while in the psycho-metric area, there are at least eight dimensions for studyinghealth status, as follows: social functioning; physical func-tioning; role-physical; bodily pain; general health; vitality;role-emotional, and mental health (20). Inclusion of the lat-ter dimensions is necessary because health status assess-ment is becoming an increasingly common and importantcomponent of both health policy evaluations and clinical re-search (29) and in the future of health economics.

Table 3.

Utilization data for diabetic vs. non-diabetic patients using Medicare data, 1993

Diabetic patients(

n

5

2,003) (1998

b

)Non-diabetic patients(

n

5

10,517) (1998

b

)

Total physician visits (

6

SD) 6

6

6 4

6

5Total physician charges (

6

SD) (USD) 3,346

6

6,337 (3,436) 1,973

6

3,971 (2,026)Total physician reimbursement (

6

SD) (USD) 1,411

6

2,655 (1,449) 872

6

1,972 (895)

,

1 day spent waiting for appointment with a physician (%) 94 95Out-patient data

No. of patients with

.

1 visit HHA (%) 13.5 7.2Total out-patient bills (

6

SD) (USD) 1.28

6

5.9 (3.37) 1.04

6

4.12 (2.09)Total out-patient reimbursement (

6

SD) (USD) 541

6

2,143 (556) 319

6

1,298 (328)In-patient data

Admission to hospital from Emergency Room (%) 51 39In-patient charges (

6

SD) (USD) 5,790

6

369,404 (5,946) 3,036

6

401,622 (3,118)In-patient reimbursement (

6

SD) (USD) 2,746

6

7,632 1,561

6

6,089 (1,603)Total costs

Total reimbursement (

6

SD) (USD) 6,847

6

15,071 (7,032) 3,773

6

9,971 (3,875)Total part A reimbursement (

6

SD) (USD)

a

3,546

6

9,108 (3,642) 1,908

6

6,838 (1,960)Total part B reimbursement (

6

SD) (USD)

a

1,956

6

4,057 (2,009) 1,196

6

2,711 (1,228)

a

Part A includes hospital insurance, finances in-patient hospital services, posthospitalization rehabilitation in skilled-care nursing facilities, and hospice carefor the terminally ill. Part B covers supplemental medical insurance, pays for physicians’ services and out-patient hospital services, diagnostic tests, laboratoryservices, and durable medical equipment (10);

b

Estimation for 1998, taking 1.027 as the inflation rate reported by the State Tax Commission, STC BulletinNo. 11. 1998.

Table 4.

Physical functioning of diabetic vs. non-diabetic patients related to physician visits and number of in-patient days, 1993

Diabetic patients(

n

5

2,003) (%)

Non-diabeticpatients

(

n

5

10,517) (%)

Wasson Health Status ClassificationNo IADL 719 (36) 5,274 (50)

Physician visits (

6

SD) 0.96

6

9 0.56

6

7Number of in-patient days (

6

SD) 1.2

6

6 0.73

6

41–2 ADL 786 (39) 3,285 (32)

Physician visits (

6

SD) 7

6

32 3

6

20Number of in-patient days (

6

SD) 3

6

8 2

6

7

.

3 ADL 341 (17) 1,082 (10)Physician visits (

6

SD) 37

6

85 23

6

67Number of in-patient days (

6

SD) 8

6

17 4

6

11ADL disability score (

6

SD) 8.47

6

15 5.8

6

13IADL disability score (

6

SD) 7.36

6

8 5.7

6

8

Salas et al. / Archives of Medical Research 31 (2000) 223–227

227

In conclusion, self-perception of physical functioning hasa close correlation with the cost of medical care in diabeticpatients and may have an important impact on determiningoutcome. These data may be used in planning educationalprograms for diabetic patients. This program must be orientedto the management of diabetes and environmental factors inorder to improve physical functioning with direct impact oncost. Improved access to preventive care may improvehealth perception and provide use of the emergency depart-ment with a more rational application of resources.

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