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Science of Economics

One of the major themes of a recent article by Guyatt and Evans which focused on the economic considerations for helminth control ~ is that the lack of helminth infections has been dampened by a 'lack of precise quantitative data on the nature and extent of morbidity associated with disease'. This is followed by a concluding statement that 'economic studies have the potential to attract funds for helminth control by demonstrating the economic burden imposed by the diseases' and that the major reason as to why funds have not been focused on these diseases is the 'lack of quantitative information on the impact of disease and control of morbidity'.

All of this presents a muddled picture of the real issue and I would like to focus on our work in Sudan, over the past 13 years, to make the point. First, there is plenty of 'precise quantitative data on the nature and extent of morbidity' associated with schistosomiasis in Sudan 2 s The problem of proving that this level of morbidity has a clear economic impact on life within these villages is difificult if not impossible to assess. Short of death, which must be directly attributable to the disease, I really cannot see any way around this dilemma. More importantly, it is my belief that the need to generate an 'economic case' for a disease that threatens the life of numerous Sudanese villagers is dangerous and could be extrapolated to the question of the economic significance of Somalia to the wodd economy. As a former student of the

'science of economics', one can see why my enchantment with this dismal science was lost in my youth.

References I Guyatt, H.L. and Evans, D. (1992) Parasitology

Today 8, 397402 2 Saad, A.M.A. etaL (1991) Brstj. Surgery78,

1252 1253 3 Homeida, M.A. et al. (1988) Arn.j. Trap. Med.

Hyg. 39, 196 20 I 4 Homeida, M.A. et al. (1988) Lancet ii, 437 440 5 Homeida, M.A. et at. (1988) Am.j. hop. Med.

Hy~ 38, 86- 9t

Jim Bennett Life Sciences Building Department of Pharmacology and Toxicology Michigan State University East Lansing MI 48824-1317, USA

Reply

It has long been recognized that priorities for health interventions in developing countries cannot be set solely on the basis of a comparison of the burden of illness of different diseases. Information is also required on the feasibility and costs of intervening, and the reduction in the burden of illness that would ensud,2. However, burden-of-illness calculations in terms of biomedical markers (such as mortality, and the duration and severity of morbidity) reveal the magnitude of the health problems facing a country, and can alert govemments and donors to neglected problems.

This has two implications for the present discussion. • First, cost-of-illness (or economic impact) studies can provide useful supplementary information on the nature and extent of health problems. It seems to be a fact of life that some bilateral donors find such estimates useful in justifTing allocating funds

to health rather than to the sectors traditionally thought of as 'productive'. We share Bennett's concern that decisions should not be made solely on this basis, as calculations can at times degenerate into a form of competitive bidding between the different diseases for aid funds. However, if schistosomiasis does drain the productive potential of people in endemic areas as commonly believed 3, and if demonstrating this can attract extra funds for control, pragmatism suggests it is worth making the calculations. • The second implication concerns the need to compare the potential benef~s (in terms of the reduced burden of illness or suffering) with the costs of an intervention. Public resources available for health care are becoming increasingly scarce, partly as a result of the economic downtum in both developed and developing countries, and partly as a result of structural adjustment policies encouraging a reduction in govemment expenditure 4. Governments are being forced to consider whether proposed health interventions are good

buys, or if the scarce resources could be used better elsewhere. Cross-disease cost-effectiveness comparisons are an inevitable result.

The pioneering ultrasound work Bennett refers to demonstrated, among other things, that chemotherapy for schistosomiasis mansoni can prevent the development of Symmers' fibrosis in children, and may result in the reversal of such pathology in adults s. The published results, however, are not in a form which allows the impact to be quantified in terms of the commonly used outcome measures in cost-effectiveness analysis leg. quality adjusted life years (QALYs) or Healthy Years of Life Lost]. This is even more pertinent to the less-severe forms of morbidity associated with schistosomiasis. It is, therefore, the lack of precise epidemiological information, in a form which can be used to assess if helminth control is a good buy, that is the problem.

Our paper offered three practical suggestions about how researchers could