Key Health Data for the West Midlands 2000

Chapter 3: Burden of Disease and Health Care Expenditure

Contacts

Preface

Contents

List of Tables
List of Figures

Abbreviations

Main Body

1: West Midlands Geography
2: Inequalities and Health
3: The Burden of Disease
4: Communicable Disease
5: Environment and Health
6: Progress on Targets set by "Our Healthier Nation"
7: Crime and Health
8: Drug Misuse

3.1 Introduction

This section uses Disability Adjusted Life Years (DALYs), a World Bank measure of the Burden of Disease to estimate disease burden in the region which is then compared with health care expenditure.

DALYs were designed as a unit to measure burden of disease. DALYs include not only premature mortality but also morbidity and are therefore more sophisticated methods of determining the burden of disease compared for example, to crude death rate, Years of life lost (YLL) or measures of disability alone. It is thought that they may be useful in informing NHS investment decisions. In order to accomplish this latter aim a detailed work on costing also has to be undertaken, the end result of which is the ‘cost per DALY’.

We have concentrated on a group of ‘Top 8’ selected conditions. These are coronary heart disease (chd), lung cancer, stroke, suicide, Alzheimer’s disease and other dementias, alcohol dependence, osteo-arthritis and schizophrenia. These diseases were selected in a previous report, of the South and West Health Authorities¹. We are aware that there are many other diseases which should be included for various reasons i.e. they are major causes of premature mortality or morbidity or have high costs associated with their management. It is possible to calculate DALYs for a large number of conditions with relative ease and therefore the report could be built upon if necessary.

The report and this chapter are of greatest use to readers who are interested in how the burden of disease varies between these selected conditions and also in how this varies between populations.

3.2 Methods

DALYs are calculated by combining two separate measures of burden of disease; years of life lost (YLL) and years of life lived with a disability (YLD).

3.2.1 Years of Life Lost (YLL)

To reflect the fact that death due to disease in the young contributes a greater loss of life (burden) than death in the elderly, we can use a measure which calculates the number of years of life lost from that disease, known as Years of Life Lost (YLL). The YLL calculation makes an assumption about a person’s natural life span using for example the standard life table

YLL were calculated for the 8 selected diseases/conditions and for total ICD9 (International Classification of Disease Volume 9) chapters, with the exception of chapters XVI (signs, symptoms and ill-defined conditions) and XVIII (supplementary classification) for which data were not available.

For any given group (5 year age group by sex) of premature deaths, in a given year:

Years of life lost are calculated for each age group (0-4, 5-9 etc to 80-84 and 85+) by sex for each individual disease/condition and each chapter using ICD9 classifications to define conditions.

3.2.2 Years of Life Lived with a Disability (YLD)

Clearly burden of disease also requires a measure of disability, for which both numbers year on year and severity need to be taken into account. Years of life lived with a disability (YLD) can be calculated by applying UK prevalence data (or if not available European or even US data) and knowledge about disease length/survival to local population data taking into account age and sex distributions.

Where local data are not obtained, i.e. for all remaining conditions (by ICD9 Chapter) Global Burden of Disease rates for the Established Market Economies (EMEs) have, been used to calculate YLD. These are calculated by the World Bank and the EME’s are taken to be the EU, USA, Canada, Australia, New Zealand, Japan and Norway.

YLD were similarly calculated for the 8 selected diseases/conditions and for total ICD9 chapters, using Global Burden of Disease data for the remaining conditions, with the exception of chapters XVI (signs, symptoms and ill-defined conditions and XVIII (supplementary classification) for which data were not available.

For any given group (5 year age group by sex) with premature disability, in a given year:

Where prevalence data is used the duration of disease will be 1 year.

3.2.3 Disability weightings

Disability weightings devised by the World Bank (updated in 1996) are then applied to the different diseases/conditions.

3.2.4 Age Weighting and Discounting

We have chosen not to age weight (to give more weight to a life lost or lived with a disability among young adults) or discount (give more weight to years of life lost and lived with a disability now compared to those in the future). Further explanation can be found in the full report.

3.2.5 Expenditure

The costing section of this project aims to provide a detailed picture of NHS expenditure, by disease groups for each health authority. The method used follows a “top-down approach” to apportioning total expenditure. The strengths and weaknesses of this approach are discussed in the South and West DALY document.

3.2.6 Cost per DALY

Calculating the cost per DALY provides an estimate of expenditure rate per DALY for individual diseases and groups of diseases (ICD9 chapters). These values can be plotted on a scatter graph with a line showing average cost per DALY shown.
For each selected condition/chapter:

Cost per DALY = Total Expenditure / Total DALYs

Since it was not possible to apportion expenditure to the individual mental health disorder, namely schizophrenia, Alzheimer’s and alcohol dependence, the cost per DALY can only be calculated for the total mental health chapter of the ICD9. Suicide cannot be calculated due to problems with the expenditure data. Therefore it is included in total expenditure of the injury and poisoning chapter.

For those chapters which include one of the other 8 diseases i.e. chapter VII - Circulatory diseases (including coronary heart disease and stroke), chapter 1 - Neoplams (including lung cancer) and XIII - Musculoskeletal diseases (including osteoarthritis) the cost per DALY is calculated for the remainder of the chapter once the diseases of the top 8 have been removed. Again due to problems with assessing YLD for chapters XII and XVI these chapters are not included.

Figure 3.7 shows cost per DALY, the relationship between disease burden and expenditure. The mean cost per DALY line can be used as a comparator, those diseases or groups of diseases to the left of the line have a higher than average cost per DALY i.e. health service expenditure compared to disease burden while those to the right of the line have a lower than average cost per DALY.

3.3 Results for the West Midlands Regional Health Authority 1997/8

Total DALYs for the top 8 diseases = 398,331
Total DALYs for ICD9 chapters = 1,721,234
Total Expenditure = £2,594,620,400

Figure 3.1: The burden of disease from 8 selected conditions using DALYs

Figure 3.2: DALYs per 1000 population from 8 selected conditions

Figure 3.3: DALYs per 1000 population for the West Midlands Region by ICD9 chapter

Figure 3.4: Cost of 6 of the 8 selected diseases in the West Midlands Region.

Figure 3.5: Total Health Expenditure by ICD9 chapter.

Figure 3.6: Health expenditure across the West Midlands by service type.

Figure 3.7: Disease Burden and Expenditure (cost per DALY) for the West Midlands.

Figure 3.8: Total Expenditure per 100,000 population by District Health Authority

Figure 3.9: Age standardized YLLs for Coronary Heart Disease (comparable between DHA)

Figure 3.10: Age standardized YLL for lung cancer (comparable between DHAs)

Figure 3.11: Age standardized YLL for stroke (comparable between DHAs)

Figure 3.12: Age standardized YLL for Suicide (comparable between DHAs)

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