Population Studies in Cardiothoracic Surgery in SA.

Anthony Linegar MBChB., FC(Cardio)SA., Ph.D.

Registrars’ Symposium Bloemfontein, June 2011.

Faculty of Health SciencesDept. Cardiothoracic SurgeryUniversity Free State

What is population health?... Refers to health status and health status inequities of populations and subgroups over time. Populations not individuals are the focus of action.

Rapidly evolving, multidisciplinary science that includes:-

Kindig D, Stoddart G. Am J Public Health. 2003 Mar;93(3):380-3. Department of Population Health Sciences, University of Wisconsin-Madison School of Medicine

Health outcomes

- Measurement- Analysis

(Dependant variable)

Health determinants

- Patterns(in-dependant

variable)

Policies & Interventions

Why population studies / health service research?

Establishes the facts (need, population, specialty)

Positions the specialty within historical and current health care context

Why population studies / health service research?

Illuminates weaknesses and strengths in the system

Strategic planning in health care delivery and in individual career planning.

How to translate research evidence into health care policy.

Health service research looks at effectiveness of health care.

• Depends on the specific research question,

• Method to be used:-

Observational (cohort, case-control, cross section,)

Experimental trials (randomised, non-randomised)

• Relationship association and causative

Cohort study – follow up study•Observational •Not randomised

• Identify a group who all share specific characteristics (alcohol consumption > 7 units per day) but healthy subjects

•Follow for pre-selected outcome (cirrhosis)

•Compare to population outside the cohort (control)

Case control •Observational •Not randomised

•Select patients with a disease (lung ca) as the starting point

•Select patients without the disease•Then measure exposures that might have a

causal relationship (smoking)

•Selection is prone to bias•Not able to establish a cause: effect but

establishes an associative relationship

Cross section study

•Assess the whole of a population

•Disease and exposure are measured simultaneously in a population

•Snap shot of disease prevalence and characteristics at one point in time.

•Cause and effect are not certain as it may not be clear which came first as they are not chronologically studied

Randomisation

•Starting point is one group split into 2 and therefore supposed to be as similar as possible

•Split created by random process•Blinded•Double blinded

•Therapeutic intervention applied to one group and comparisons made on outcomes of the two groups

Terminology

•Epidemiology investigates distribution and determinants of disease

•Health economics studies the financing of health care systems, quantifies the value of service provided, models decision making, attempts to influence the application of available resources.

•Operational research

What measures do we use?

• Crude incidence • Incidence = new cases per year / population x

100,000 (time based definition)

• ASIR

• Standardisation – adjustment to remove effect of differences in a composite population This minimises erroneous comparisons.

• Mortality rates crude = deaths per year/ population X 100,000

Measures continued

•Prevalence is not expressed per unit time = total cases at one point in time / population this is not a rate.

•Clinical activity

•Performance gap

Why population studies / health service research?

Informs about:-

burden of disease

service delivery

performance gap

Burden of disease in community

Clinical activity within the burden of disease

Research activity

Clinical governance

Linegar AG, 2008

A word on literature reviews - sources

•MEDLINE via search engine PUBMED; 16 million citations since 1950

•OVID•EMBASE•CINAHL•Cochrane Library for clinical trials and

systematic reviews. •African database (Africa-Wide:NiPad) •SA non-reviewed journals

A word on literature reviews

•Simple review

•Bias; selection; exclusion; incomplete; sample size inadequate; lacks relevance; needs a great deal of explanation.

•Value determined by the research question and the aim of the literature review.

A word on literature review

•Systematic review

•Starts with a predetermined aim and a clear and reproducible method, limitations are noted

•Duplication by another researcher should reveal the same results – reproducible

•Analysis of results requires meta-analysis

Study example in Rheumatic HD, Congenital HD, Thoracic surgery.

1. Research question 2. Aim of the study 3. Objectives of the study 4. Method

Example

1. Research question based on a hypothesis- the performance gap in TSY in CSA

2. Aim - to design a model

3. Objectives - Qt burden of disease- Qt clinical activity - Qt performance gap

4. Method- define the population - define the time period of the study - quantitative burden of disease study- Mixed methods

Health study in CSA•Mixed methods study – Performance gap

in TS •Aim to create a model for the

development of thoracic surgery •2004-2006•Population 5.2 million (HDI 121st )•86% dependant on state health care

provision •One department CTS (Bloemfontein)

- 3 consultants, 4 registrars- 8 bed ICU and 22 ward beds

Methodology

• Burden of disease in community

• • Clinical activity within the burden of disease

• Research activity

Demographics CIR, ASIRDisease specific Mortality DataStats SA, HST, MRC National Cancer Registry Publications (large series over finite time period)

Departmental statisticsRegional and tertiary hospitals Private CT Surgeons statistics Private medical aidsICD 10 codes Operation codes Other disciplines (Gen Surg)No. of surgeons (WTE)

Systematic review all publications

The next step - implementation

Situational analysis

Set goal of model

Define elements of the system

Identify constraints in system

List possible solutions

Prioritise for implementation

Determine performance measures

Implementation phase

Cycle begins again with audit using performance measures

Any solution to promote accessto and efficiency of thoracic surgery

service provision

Bottlenecks in patient access to service as well as the

efficiency of thoracic surgery in providing service

Building blocks of the system

The overall goal of the model that defines its purpose

For later audit

Choose which solutions to implement

and in what order

Situational analysis

Set goal of model

Define elements of the system

Identify constraints in system

List possible solutions

Prioritise for implementation

Determine performance measures

Implementation phase

Cycle begins again with audit using performance measures

Any solution to promote accessto and efficiency of thoracic surgery

service provision

Bottlenecks in patient access to service as well as the

efficiency of thoracic surgery in providing service

Building blocks of the system

The overall goal of the model that defines its purpose

For later audit

Choose which solutions to implement

and in what order

The ATLAS Project: Premise for analysis.

Qt Size of population and Burden of Disease / 100,000

Incidence ~Prevalence ~ Mortality

Resectability / Operability 10 – 20%

Calculate required number of lung resections

Atlas project: resultsThe top ten causes of cancer mortality in SA (persons) (Bradshaw et al., 2003).

Rank Cause of death Number of deaths % of cancer deaths

1Cancer of Lung Trachea Bronchus 7173 17.2 %

2 Cancer of Oesophagus 5803 13.9%3 Cervix cancer 3424 8.2%

4 Breast cancer 3062 7.3%

5 Liver cancer 2692 6.5%

6 Colo-rectal cancer 2446 5.9%

7 Prostate cancer 2411 5.8%

8 Stomach cancer 2365 5.7%

9 Pancreas cancer 1530 3.7%

10 Mouth and Oro-pharynx cancer 1464 3.5%

All Cancer deaths 41691 100%

Annual SA mortality: MRC vs Stats SA

1997 1998 1999 2000 2001 2002 2003 2004 2005

Stats SA

316507 365053 380982 414530 453404 499925 553718 572350 591213

BOD Unit

NaN NaN NaN 556585 NaN NaN NaN NaN NaN

50000

150000

250000

350000

450000

550000

650000

Years

Death

s

Stats SA 2005.

34%

Age Standardised death rates in SA.

Cause specific mortality rates in SA and FS 2000 (Bradshaw et al., 2003).

Cause of death Age std death rate / 100 000 population SA

Number of deaths SA(pop = 45m)

Number of deaths FS(pop = 2.9 m)

Estimated number of deaths for Central SA (pop = 4.6 m)*

HIV/AIDS 349.9 165 859 11796 16130

TB 83.5 29 803 2422 3849

Homicide 72.5 32 485 1327 3342

LRTI 64.8 22 097 2249 2987

COPD 49.3 12 473 737 2272

Road traffic accident 43 18 446 811 1982

Lung cancer 26.4 7173 369 1217

Oesophagus cancer 20.9 5803 258 963

The ATLAS Project: Burden of disease based on ASDR.

26.4 per 100,000 in 48m – 50 m population

12672 – 13200 deaths per annumActual recorded deaths 2008 = 7131

713 - 1320 operations/ annum (10% resect)

1426 – 2640 operations/ annum (20% resect)

Clinical activity: lung resectionsTable 5.3 Operations performed during 2006 at teaching hospitals in SA.

A B C D E F GTotal operations 268 463 1186 190 413 dna 210

Pneumonectomy(all pathologies) 7 11 19 8 21 dna 15

Pneumonectomy (lung cancer) 0 nk 4 0 nda dna 0

Lobectomy (all pathologies) 16 26 69 15 23 dna 11

Lobectomy (lung cancer) 7 nk 10 3 dna dna 0

Bullectomy 1 27 4 5 14 dna 0Pleurectomy 2 27 11 2 0 dna 0Lung reduction 0 0 0 0 0 dna 0

Open drain empyema 5 0 27 5 8 dna 0Decortication 2 55 17 24 6 dna 23Fenestration (Eloesser) 0 0 0 0 7 dna 2Thoraco-myoplasty 1 0 0 2 4 dna 1

Oesophageal stent 29 15 50 0 0 dna 10Oesophagectomy 3 1 14 3 2 dna 2Benign oesophageal 0 0 0 0 0 dna 0

Mediastinoscopy 14 15 30 19 29 dna 6Mediastinal mass 4 3 0 2 9 dna 0

Trauma operations 9 116 2 1 0 dna 0

Sympathectomy 0 0 0 1 0 dna 0Thoracic outlet 0 0 0 0 0 dna 0

Private sector lung resections 2005 SA 2006 SA

All Drs CTS All Drs CTS

Admissions 1209 281 1357 328

Admissions per 100,000

30 9 42 10

Lung resections 25 25 23 21

Scale up Medscheme and Discovery data to represent the whole privatepopulation = 38-45 cases per annum

The performance gap Burden = 713 – 1320 operations required per annum in state and private in SA

Operations for lung cancer done annually = 20 – 30 in 7 University Hospitals = 45 resections in private

Total resections = 65 – 75 per annum

Performance gap for SA as a whole 1 : 10 to 1 : 20

What does this mean?Clinical service provision

90% to 95% of expected resections are not done

As a complete resection provides the only chance of potential cure for these patients

Most potentially curable patients are not adequately treated

Task

1. Design a study plan in your region to explore the following - Rheumatic HD- Congenital HD- Thoracic surgerywith respect to burden of disease; service provision; identify possible solution pathways

2. Bring results to next annual meeting