Healrh Policy, 5 (1985) 159-164 Elsevier

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HPE 00049

Cost-effective control of rheumatic fever in the community

Toma Strasser Department of Social and Prevenrive Medicine, University of Geneva, Geneva, Switzerland

(Accepted for publication 27 May 1985)

Summary

Rheumatic fever is declining rapidly in importance in the developed countries, but is still a major public health problem in the developing countries. Primary prevention techniques, consisting of the detection and antibiotic treatment of streptococcal infections of the pharynx, are both feasible and effective, but are also costly, as only lo-20% of all pharyngeal infections are due to the beta-hemolytic Streptococcus, and only a small proportion of those actually develop into rheumatic heart disease. A different concerted approach, which is both effective and economically entirely justi- fiable, is to use antibiotics as a prophylaxis to prevent secondary infection, i.e. relapses of rheumatic fever.

A multi-centre study conducted by the WHO has shown that the cost of antibiotics used for secondary prevention was less than the savings resulting from the lower incidence and shorter hospital stays of recurrencies of rheumatic fever.

Given economic restrictions, therefore, priority is given to organized and systematic secondary prevention.

secondary prevention; cost-effectiveness; rheumatic fever; developing countries

Rheumatic fever is still with us today. Though medical students in Europe and North America may now be fortunate enough not to see a single case of acute rheumatic carditis during a 5-6 year curriculum, rheumatic fever is far from being eradicated from our planet, like so many other diseases originating from poverty and aggravating the vicious circle of poverty-disease-poverty,

Address for correspondence: Dr. T. Strasser, Institut de Mtdecine Sociale et PrCventive, 27, Quai Charles- Page, CH-1211 Genkve 4, Suisse.

0168-8510/85/$03.30 0 1985 Elsevier Science Publishers B.V. (Biomedical Division)

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The International Society and Federation of Cardiology declared 1984-1985 the “Year of the Rheumatic Child” to stimulate the control and prevention of rheumatic fever and rheumatic heart disease in developing countries [I]. This is an appropriate opportunity to review the control and prevention of this disease, particularly the effectiveness of the various existing approaches.

Rheumatic heart disease is, at least theoretically, a pre-eminently preventable condition, in fact the only readily preventable heart disease. Yet, with all its crippling consequences, it is still common in developing countries. Recently published informa- tion includes prevalence rates in school children in Latin American countries of around 10’/& in cities such as Caracas, Montevideo, SEo Paulo or Pot-to Allegre [2]; or, in Asian countries, of 1 1°& in New Delhi and 8*1, in Vellore (India), 7-8”/00 in Pakistan or 1.9-2.5y00 in Thailand [3]. Prevalence is particularly high in urban slums. Though these figures are far from being reliable, they may serve as indicators of the magnitude of the problem.

Barriers to primary prevention

Why is rheumatic heart disease still so prevalent? The throat infection by group A Streptococcus is easily cured by a single injection of benzathine penicillin, which then prevents further development of rheumatic fever, of subsequent acute rheumatic carditis and, later on, of chronic (valvular) rheumatic heart disease. Throat infection, however, is one of the commonest acute diseases of the human species, and only some IO-20% of them are caused by streptococci, the rest being of viral origin. A streptococ- cal throat infection evolves in some l-2% into rheumatic fever, which in one out of three cases may result in rheumatic heart disease. For each such case, however, one should count one case of rheumatic heart disease that has not apparently been preceded by acute rheumatic fever, or a clinically manifest streptococcal infection. Therefore, in order to prevent 100 cases of rheumatic heart disease, at least 200000 cases of acute throat infections should receive appropriate medical care [4], a figure that seems discouraging from the point of view of feasibility and of cost-effectiveness.

Such computations are obviously very sensitive to the various underlying numerical factors which, on their part, may depend on the physical and social environment of a country. Thus, in another similar calculation made for a tropical developing country it is assumed that 3% of children with group A streprococcal pharyngitis develop rheumatic fever leading in 3 out of 4 cases to rheumatic heart disease. The proportion of treated pharyngitis to potentially prevented heart disease is thus less unfavourable than in the first calculation, leading to the conclusion of a 5.4 : 1 presumptive cost-ef- fectiveness ratio in favour of pharyngitis treatment by penicillin, provided that only group A streptococcal throat infections are treated [5].

Is this a plausible policy in reality? Yes, but only under optimal conditions, with all such penicillin treatment being preceded by a reliable bacteriological diagnosis of each (or most) case(s) of pharyngitis. This is hardly possible ina tropical, developingcountry though quite feasible in an affluent society. In fact, it was done in the 1960s in a number

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of community programmes for the control of rheumatic fever in the U.S.A. Never- theless, a few years ago the issue of finding the optimal policies of management of acute pharyngitis with respect to cost-effectiveness was re-examined in the U.S.A. [6-81. While there was agreement that in epidemic situations all persons with acute pharyngi- tis should be treated with penicillin, there was disagreement as to which are the most cost-effective procedures in endemic situations, i.e. whether the decision to make throat cultures should be shaded according to the prevalence rate of positive findings of streptococci in a population, or whether as a rule a bacteriological diagnosis should first be established. The most reasonable and cost-effective recommendation (for the U.S.A.) seemed to be to “. . . treat endemic pharyngitis only after throat culture results are known. Some patients may be properly treated before culture results are known: (a) patients with a past history of rheumatic fever not on prophylaxis; (b) young patients with a strong family history of documented rheumatic fever; and (c) patients with scarlet fever” [8].

The crux of the matter is, however, that this recommendation applies to developed countries. If one assumes that rheumatic fever is 25 times as frequent in the developing as in the developed world, and considering that only some 25% of the world’s population live in developed countries, the recommendation to wait for a throat culture before giving penicillin may not apply to 98.7% of the world’s potential rheumatic fever patients.

Is there a way out, besides dispensing penicillin to all children with different forms of pharyngitis all over the world, with all the obvious biological, ecological and financial costs such a measure would imply? One solution would be to bypass the throat culture technique by finding an inexpensive and instant diagnostic procedure for the identifi- cation of group A beta-haemolytic streptococci. An immunoenzyme technique for direct identification of streptococci has been elaborated recently as a rapid and widely applicable test, hopefully inexpensive. It is now being validated in a collaborative study coordinated by the WHO (unpublished). If it proves to be reliable and inexpen- sive, the test might greatly facilitate the diagnosis of streptococcal infections in primary health care under unsophisticated conditions.

A much more significant advance in the prevention of rheumatic fever would be the elaboration of a vaccine against streptococci, which would permit primary prevention of streptococcal infection itself. Research in this field has been going on for decades, the difficulty being that immunity to streptococci is type-specific, and the number of pathogenic types is very great. Though some progress has been achieved, a safe and efficacious vaccine is still a promise, rather than reality.

Effective community action

In the meantime, however, rheumatic fever is with us and calls for action. At by far the greatest risk of rheumatic heart disease or its deterioration are children and adolescents who have already had an attack of acute rheumatic fever. It is of great importance and urgency to organize the prevention of recurrences in these high risk individuals since past experience indicates that secondary prevention is likely to remain highly ineffective.

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Organized, systematic and effective prevention of recurrent rheumatic fever is possible in developing countries, in the form of community control programmes; this has been demonstrated by a WHO multi-centre project carried out in a number of developing countries, including Barbados, Cyprus, Egypt, India, Iran, Mongolia and Nigeria [9], as well as several Latin American countries. The objectives of this project were to detect, register and follow-up persons (mainly children and adolescents) who had suffered an attack of acute rheumatic fever, in order to ensure the regular administration of benzathine penicillin injections with the aim of preventing recur- rences of rheumatic fever and progression of rheumatic heart disease. A scheme of the organization of a community programme shows the health service elements involved in the programme with their multiple relationships (Fig. 1).

During the observation period of 5500 patient-years different levels of effectiveness of prevention were achieved, since not all registered patients complied satisfactorily with the regimen of monthly penicillin injections.

In some 20% of all the observation years only up to 5 injections were given (prophylaxis none or ‘occasional’); full or regular prophylaxis (12, 11 or 10 injections) was given in some 60%, while the rest constituted the group of irregular prophylaxis (6-9 injections per year).

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Fig. 1. Chart of functional relationships.

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The 20% rate of poor prophylaxis (O-5 injections per year) indicates the limits to effectiveness of this type of community programme in developing countries; whether such effectiveness is considered high or low is a matter of subjective judgement. There are, however, objective ways of measuring the effect of the programme.

In this respect, the following example may be given. In the WHO project [9], patients at various levels of penicillin prophylaxis had various rates and lengths of hospitaliza- tion: those on irregular, occasional or no penicillin prophylaxis spent on the average six times as much time in hospital as those on full prophylaxis. The computed actual gain thus achieved by the prevention programme amounted to nearly 9500 hospital days averted by regular prophylaxis; the potential gain that could have been realized, had those on poor prophylaxis been also on a regular prophylactic regimen was computed at approximately 6500 days [9]. In monetary terms, the actual gain in hospital days by far outweighs the cost of penicillin given and thus justifies the programme from the health economics point of view; the imponderable but more important health benefits were thus achieved at no financial cost. If the relation of the actual and potential gain in hospital days is considered, this programme was operating with an efficiency of 60%; once again, it is a matter of subjective evaluation whether this coefficient is considered high or low, but there is no doubt that the programme was effective.

The role of socio-economic development and the need for prevention

Community action to combat streptococcal infections is thus effective, but the well known fact should be stressed again that the very significant decline in rheumatic fever and rheumatic heart disease in developed countries is primarily due to other factors. As first shown in Denmark, the decline of rheumatic fever incidence became evident some hundred years ago, ever since it became a notifiable disease in that country [lo], and there is a remarkable congruence of practically all recent information on this decline which is seemingly connected with socio-economic development [ 1 I]. When considering rheumatic fever in the context of history [l 11, there is little doubt that socio-economic improvement is the most effective, most powerful factor in the control of rheumatic fever. But wherever socio-economic development is lagging, as it does in most of the third world, or, for that matter, in the islands of poverty or neo-poverty within societies of affluence, organized rheumatic fever control should be instituted: it is effective.

References

1 ISFC Committee on Prevention of Rheumatic Fever and Rheumatic Heart Disease. Heartbeat,No. 2, July 1983, p. 1, and No. 4, December 1983, p. 10.

2 Pan American Health Organization: Prevencton y control de la fiebre reumatica en la comunidad. Manual de normas operativos para un programa de extension de la cobertura en 10s diferentes niveles de atenci6n. Washington, D.C., PAHO, 1980, Publication Cientifica No. 399.

3 Guzman, S.V. and Linson, B.B., Rheumatic fever - rheumatic heart diseases: Epidemiology and pathogenesis. Proceedings of the VII Asian-Pacific Congress of Cardiology, 1979, Bangkok, Thailand.

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