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Lutte contre le trachome en Afrique subsaharienne

 | 
Anne-Marie Moulin
, 
Jeanne Orfila
, 
Doulaye Sacko
, 
et al.

Part One. Synopsis and recommendations. English Version

The financial argument

Texte intégral

ECONOMIC CONSEQUENCES OF TRACHOMA AND ECONOMIC IMPACT OF TREATMENT

Cost-utility analyses

1Recently, there have been economic analyses concerning trachoma. Economists and epidemiologists measure the seriousness of a disease in DALY (Disability Adjusted Life-Years). For any disease, this parameter measures the number of years lost and the deterioration in the quality of life of the years left to live. This indicator allows us to compare the seriousness of trachoma with that of other diseases.

2The number of DALY lost because of trachoma is twice as much in Africa as in China and India for a much smaller population. In Africa, there is almost as much trachoma as cases of cataract, whereas in India there are six times more cases of cataract. Trachoma is much more significant than leprosy in Africa. In terms of DALY, in Africa, trachoma is a lesser priority than infectious diseases like measles. However, the prevalence of it remains high. It should be emphasized that its relative place increases with the epidemiological transition marking the retreat of most infectious diseases.

3The consequences of trachoma are generally underestimated because they are only felt later in life after the initial infectious episode; often among people over fifty years of age and more frequently among women. The amount of blindness among elderly women does not appear fully when using the DALY because their life expectancy at this age is reduced. The value of the DALY also depends on the way of quantifying the disability. The rate of disability of 60 %, often employed for complete blindness, is probably underestimated. These calculations do not take into account the pain caused by trichiasis not yet accompanied by total blindness. Recent research has shown that this pain is incapacitating and hinders the daily activity of women. Among children, the pain caused by inflammatory trachoma is not taken into account either, even if it can have a big impact on their physical and mental development. Finally, the shorter life expectancy of blind people must also be taken into account.

Cost-benefit analyses and research prospects

4For a more complete economic analysis, which could be used for comparisons with other non-medical programs, it is necessary to develop benefit and losses from a monetary point of view. In cost-benefit analyses (in comparison with cost-utility analyses using the DALY), we measure the losses or gains in productivity. This measurement (sometimes based on the average of the GNP) is rather coarse. Not only the productivity of people in the formal sector, but also productivity of the informal sector (domestic tasks, for example) should be taken into account. The cost of assistance given to a blind person (estimated at 10 % of the time of an adult) should also be considered. Worldwide, the total loss of productivity related to trachoma may be estimated at 5.3 bn dollars in 1995.

A social impact difficult to quantify

5The social consequences of trachoma appear more meaningful when, instead of being expressed in DALY or dollars, we quite simply state the number of people affected by the problem. In Mali, the prevalence of trichiasis is estimated at 2.5 % of women over fifteen years of age. If it is considered that half of these women will become blind during the last ten years of their life, the effect of trachoma on the village community becomes much more meaningful. In villages with high prevalence, one family in ten would be confronted with the problem!

6The economic analysis must also examine the spread of the effect of trachoma according to the income of the population. At a personal level, trachoma has more of an effect on the least privileged. At the macro-economic level, trachoma has a disproportionate effect on the poorest countries, and especially on those where the value of an agricultural worker is lowest.

7Research into the economics of trachoma has developed over recent years. The first models concerned short-term costs and effects. More elaborate models concern the long term, taking into account the interaction between factors.

The economic impact and the cost of intervention

8The economic impact of the action to combat trachoma cannot be measured as simply in combating onchocerciasis, where the essential benefit, the recovery of cultivable ground, is easily quantifiable and easy to make understood by the populations. In the case of trachoma, the population greatly underestimates the possible benefit of trachoma control and does not see the benefit that patients can have from the trichiasis operation, which however brings immediate relief. One of the explanations is due to the fact that it is above all a question of preventing complications (and not curing blindness as in the case of cataracts), and that this problem often concerns elderly women.

9The cost of the action consolidated in the SAFE program varies according to the strategy chosen. The mass distribution of antibiotics (even if its good cost-effectiveness is recognized in regions of strong prevalence) requires sizeable budgets if it covers the country or whole regions. More targeted strategies, requiring individual diagnosis, also involve considerable financial and human resources. Mobile teams engender considerable expenditure on transport. The cost of training personnel must be taken into account in all the strategies.

10The external effects (positive as much as negative) of these various strategies are not always fully recorded. They differ according to whether they are “vertical“ programs, functioning with personnel devoted exclusively to the trachoma program, or “horizontal“, relying on the existing health services or a combination of both.

  • When the programs use the resources of the existing health services, they can reinforce them by offering the personnel further training and/or secondary benefit (vacations, means of transport, etc), encouraging them to strengthen their contacts with their communities by increasing their prestige and job satisfaction. On the other hand, the time devoted to combating trachoma by some of the personnel at the post can make them neglect routine tasks.
  • In the case of vertical programs, comparison between the distribution of antibiotics by volunteers and village health centers, which often lack essential drugs, risks weakening still more the image of these centers in public opinion.

11The positive side is that certain components of the SAFE strategy, although difficult to evaluate accurately, have a potentially considerable impact on the local economy, such as improving access to water and sanitation systems.

12The war on trachoma provides a noteworthy opportunity to closely associate health workers with development work (drilling, construction of wells, improvements in education) and alert other categories of the population (teachers, engineers) about the importance of their work for public health; in short to tackle a health problem from the economic and social angle at the same time.

Conclusions and recommendations

13The economic survey of trachoma control is particularly important because of the strong competition with other infectious diseases. It is thus necessary to develop models evaluating the long-term effects of the SAFE strategy. This poses the problem of updating the future benefits. To facilitate these evaluations, it appears necessary to include economic indicators, even in the monitoring of programs.

CAN THE REDUCTION IN TRACHOMA BE USED AS AN INDICATOR OF DEVELOPMENT IN REGIONS OF ENDEMIC DISEASE?

14To measure development, economists have indicators that are not very sensitive and difficult to interpret. The growth in incomes of inhabitants, for example, is not enough to measure the level of development. Furthermore, this data is difficult to obtain in poor countries. The indicators of wealth are based on the possession of certain goods considered crucial, which differ according to the country and culture. It is difficult to prepare an overall indicator.

15The link between trachoma and poverty has been recognized for a long time, and it is thus not astonishing that the reduction in prevalence of trachoma could be proposed as a convenient and objective indicator of development. It is a reality often difficult to measure. Even more so as it appears relatively quick and inexpensive to study the prevalence of trachoma in a population, possibly during an investigation pursuing other objectives. Furthermore, the specificity and sensitivity of such an indicator need to be clarified.

16The prevalence of trachoma is due to various factors (access to water, habitat, education, hygiene, etc.) essential to human development. A high prevalence inevitably reveals the particularly difficult living conditions of a community. From this point of view, the prevalence of trachoma seems a very specific indicator of human development

17Moreover, trachoma is a sensitive indicator in that it makes it possible to quickly measure the progress of the development if the prevalence of trachoma decreases. The impact of improved living conditions on the disease can indeed be relatively rapid. In any case, it is a much more “flexible“ indicator than death or morbidity rates, which only very gradually reflect improvements in sanitary arrangements and the health services. However, if trachoma indicates the existence of poor living conditions, on the contrary, the deterioration of living conditions in an urban context for example, will not inevitably result in a reappearance of trachoma.

18In any case, investigations of prevalence of trachoma cannot replace indepth investigations into the living conditions of the populations. The prevalence of trachoma is only one indicator among others whose convergence alone makes it possible to accurately identify problems of development.

19We could even reverse the question and propose using the usual development indicators in trachoma control. It is sometimes easier to qualify local water resources than to turn over the eyelids of a certain number of children. In fact, investigations into poverty give valuable information on the risks of trachoma. Rather than a genuine indicator, trachoma must therefore be regarded as it was for two centuries, a revealer of poverty.

Conclusions and recommendations

20To conclude, the prevalence of active trachoma is a fairly sensitive and specific indicator of poverty, which overall implies difficult living conditions. However, it is not a highly reliable indicator of development. On the contrary, poverty is a good indicator, especially in the rural environment, for suspecting pockets of trachoma.

© IRD Éditions, 2006

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