Estimating the "avoidable" burden of disease by Disability Adjusted Life Years (DALYs)

Apples and oranges: a comparison of costing methods for obesity

Obesity has escalated to epidemic proportions over the past 30 years resulting in increased disease burden and healthcare costs. The aim of this paper was to analyse different costing methods for obesity. Several databases have been searched to identify eligible literature estimating obesity cost. These were categorized into databases, patient-attributable fraction (PAF) and modelling studies. Studies from the United States were used to explore effects of study designs on cost outcomes. Our results show that cost outcomes are largely affected by underlying study designs, such as population size, age, cost categories (medical expenditure vs. total costs), length of the data collection and body mass index cut-offs. Three study types are likely to have an impact on reported costs, with modelling studies providing the most conservative estimates. Database studies can help to increase the overall awareness of the economic burden of obesity. PAF studies can make the obesity disease more tangible by drawing connections to diseases. Decision makers need to be aware of the different purposes and weaknesses of the studies when interpreting cost outcomes. Further research is needed to refine the existing methods and provide high-quality data accounting for the complexity of the disease.

Cost-effectiveness of a community-based intervention for reducing the transmission of Schistosoma haematobium and HIV in Africa

Epidemiological studies from sub-Saharan Africa show that genital infection with Schistosoma haematobium [corrected] may increase the risk for HIV infection in young women. Therefore, preventing schistosomiasis has the potential to reduce HIV transmission in sub-Saharan Africa. We developed a transmission model of female genital schistosomiasis and HIV infections that we fit to epidemiological data of HIV and female genital schistosomiasis prevalence and coinfection in rural Zimbabwe. We used the model to evaluate the cost-effectiveness of a multifaceted community-based intervention for preventing schistosomiasis and, consequently, HIV infections in rural Zimbabwe, from the perspective of a health payer. The community-based intervention combined provision of clean water, sanitation, and health education (WSH) with administration of praziquantel to school-aged children. Considering variation in efficacy between 10% and 70% of WSH for reducing S. haematobium [corrected] transmission, our model predicted that community-based intervention is likely to be cost-effective in Zimbabwe at an aggregated WSH cost corresponding to US $725-$1,000 per individual over a 20-y intervention period. These costs compare favorably with empirical measures of WSH provision in developing countries, indicating that integrated community-based intervention for reducing the transmission of S. haematobium [corrected] is an economically attractive strategy for reducing schistosomiasis and HIV transmission in sub-Saharan Africa that would have a powerful impact on averting infections and saving lives.

The feasibility of canine rabies elimination in Africa: dispelling doubts with data

BACKGROUND

Canine rabies causes many thousands of human deaths every year in Africa, and continues to increase throughout much of the continent.

METHODOLOGY/PRINCIPAL FINDINGS

This paper identifies four common reasons given for the lack of effective canine rabies control in Africa: (a) a low priority given for disease control as a result of lack of awareness of the rabies burden; (b) epidemiological constraints such as uncertainties about the required levels of vaccination coverage and the possibility of sustained cycles of infection in wildlife; (c) operational constraints including accessibility of dogs for vaccination and insufficient knowledge of dog population sizes for planning of vaccination campaigns; and (d) limited resources for implementation of rabies surveillance and control. We address each of these issues in turn, presenting data from field studies and modelling approaches used in Tanzania, including burden of disease evaluations, detailed epidemiological studies, operational data from vaccination campaigns in different demographic and ecological settings, and economic analyses of the cost-effectiveness of dog vaccination for human rabies prevention.

CONCLUSIONS/SIGNIFICANCE

We conclude that there are no insurmountable problems to canine rabies control in most of Africa; that elimination of canine rabies is epidemiologically and practically feasible through mass vaccination of domestic dogs; and that domestic dog vaccination provides a cost-effective approach to the prevention and elimination of human rabies deaths.

Evaluating the cost-effectiveness of rabies post-exposure prophylaxis: a case study in Tanzania

Although fatal if untreated, human rabies can be prevented through post-exposure prophylaxis (PEP), which involves a course of vaccination and immunoglobulin administered immediately after exposure. However, high costs and frequent lack of rabies vaccine and immunoglobulin lead to about 55,000 deaths per year worldwide. Using data from a detailed study of rabies in Tanzania, we calculate a cost-effectiveness ratio for PEP when the WHO-recommended Essen regimen, a 5-dose intramuscular vaccination schedule, is adopted. Our analyses indicate a cost-effectiveness ratio for PEP of $27/quality-adjusted life year (QALY) from a health care perspective and $32/QALY from a societal perspective in Tanzania. From both perspectives, it is "very cost-effective" to administer PEP to patients bitten by an animal suspected to be rabid. Moreover, PEP remains "very cost-effective" provided that at least 1% of doses are administered to people who were actually exposed to rabies.

Adjusting life for quality or disability: stylistic difference or substantial dispute?

This paper focuses on the contrast between describing the benefit of a healthcare intervention as gain in health (QALY-type ideas) or a disability reduction (DALY-type ideas). The background is an apparent convergence in practice of the work conducted under both traditions. In the light of these methodological developments, we contrast a health planner who wants to maximise health and one who wants to minimise disability. To isolate the effect of framing the problem from a health or a disability perspective, we do not use age-weighting in calculating DALY and employ a common discounting methodology and the same set of quality of life weights. We find that interventions will be ranked in a systematically different way. The difference, however, is not determined by the use of a health or a disability perspective but by the use of life expectancy tables to determine the years of life lost. We show that this feature of the DALY method is problematic and we suggest its dismissal in favour of a fixed reference age rendering the use of a health or a disability perspective merely stylistic.

The burden of overweight and obesity-related ill health in the UK

This paper reviews previous cost studies of overweight and obesity in the UK. It proposes a method for estimating the economic and health costs of overweight and obesity in the UK which could also be used in other countries. Costs of obesity studies were identified via a systematic search of electronic databases. Information from the WHO Burden of Disease Project was used to calculate the mortality and morbidity cost of overweight and obesity. Population attributable fractions for diseases attributable to overweight and obesity were applied to National Health Service (NHS) cost data to estimate direct financial costs. We estimate the direct cost of overweight and obesity to the NHS at pound 3.2 billion. Other estimates of the cost of obesity range between pound 480 million in 1998 and pound 1.1 billion in 2004 [Correction added after online publication 11 June 2007: 'of the cost of obesity' added after 'Other estimates']. There is wide variation in methods and estimates for the cost of overweight and obesity to the health systems of developed countries. The method presented here could be used to calculate the costs of overweight and obesity in other countries. Public health initiatives are required to address the increasing prevalence of overweight and obesity and reduce associated healthcare costs.

The burden of food related ill health in the UK

STUDY OBJECTIVE

To quantify the burden of ill health in the UK that can be attributed to food (the burden of food related ill health).

DESIGN

Review and further analysis of the results of work concerned with estimates of the burden of disease measured as morbidity, mortality, and in financial terms and with the proportion of that burden that can be attributed to food.

MAIN RESULTS

Food related ill health is responsible for about 10% of morbidity and mortality in the UK and costs the NHS about 6 billion pounds annually.

CONCLUSIONS

The burden of food related ill health measured in terms of mortality and morbidity is similar to that attributable to smoking. The cost to the NHS is twice the amount attributable to car, train, and other accidents, and more than twice that attributable to smoking. The vast majority of the burden is attributable to unhealthy diets rather than to food borne diseases.

Using epidemiological data to model efficiency in reducing the burden of depression*

BACKGROUND: The Global Burden of Disease study has suggested that mental disorders are the leading cause of disability burden in the world. This study takes the leading cause of mental disorder burden, depression, and trials an approach for defining the present and optimal efficiency of treatment in an Australian setting. AIMS OF THE STUDY: To examine epidemiological and service use data for depression to trial an approach for modelling (i) the burden that is currently averted from current care, (ii) the burden that is potentially avertable from a hypothetical regime of optimal care, (iii) the efficiency or cost-effectiveness of both current and optimal services for depression and (iv) the potential of current knowledge for reducing burden due to depression, by applying the WHO five-step method for priorities for investment in health research and development. METHODS: Effectiveness and efficiency were calculated in disability adjusted life years (DALYs) averted by adjusting the disability weight for people who received efficacious treatment. Data on service use and treatment outcome were obtained from a variety of secondary sources, including the Australian National Survey of Mental Health and Wellbeing, and efficacy of individual treatments from published meta-analyses expressed in effect sizes. Direct costs were estimated from published sources. RESULTS: Fifty-five percent of people with depression had had some contact with either primary care or specialist services. Effective coverage of depression was low, with only 32% of cases receiving efficacious treatment that could have lessened their severity (averted disability). In contrast, a proposed model of optimal care for the population management of depression provided increased treatment contacts and a better outcome. In terms of efficiency, optimal care dominated current care, with more health gain for less expenditure (28 632 DALYs were averted at a cost of AUD295 million with optimal care, versus 19 297 DALYs averted at a cost of AUD720 million with current care). However, despite the existence of efficacious technologies for treating depression, only 13% of the burden was averted from present active treatment, primarily because of the low effective coverage. Potentially avertable burden is nearly three times this, if effective treatments can be delivered in appropriate amounts to all those who need it. DISCUSSION: This paper reports a method to calculate the burden currently averted from cross-sectional survey data, and to calculate the burden likely to be averted from an optimal programme estimated from randomized controlled trial data. The approach taken here makes a number of assumptions: that people are accurate in reporting their service use, that effect sizes are a suitable basis for modelling improvements in disability and that the method used to translate effect sizes to disability weight change is valid. The robustness of these assumptions is discussed. Nonetheless it would appear that while optimal care could do more than present services to reduce the burden of depression, current technologies for treating depression are insufficient. IMPLICATIONS FOR HEALTH CARE PROVISION AND USE: There is an urgent need to educate both clinicians (primary and specialist) and the general public in the effective treatments that are available for depression. IMPLICATIONS FOR HEALTH POLICIES: Over and above implementing treatments of known efficacy, more powerful technologies are needed for the prevention and treatment of depression. IMPLICATIONS FOR FURTHER RESEARCH: Modelling burden averted from a variety of secondary sources can introduce bias at many levels. Future research should examine the validity of approaches that model reductions in disability burden. A powerful treatment to relieve depression and prevent relapse is needed.