Declining Trend of Rheumatic Fever Observed
Zaman M. Mostafa
National Center for Control of
Rheumatic Fever and Heart Diseases
Sher-e-Bangla Nagar, Dhaka 1207, Bangladesh
Rheumatic fever is prevalent in many of the developing countries of the Indian subcontinent, the Arab countries of the Middle East, and the urban metropolises of Central and South America and Africa1,2 . In developed countries, it has shown a decreasing trend for more than half a century and become almost absent nowadays. However, the trend in the developing countries remains almost unknown. It is extremely difficult to ascertain the exact trend in a developing country like Bangladesh. In this study we use data of the National Center for Control of Rheumatic Fever and Heart Diseases (hereinafter referred to as the Rheumatic Fever Center) to examine the secular trend of rheumatic fever in Bangladesh.
Source of data:
The Rheumatic Fever Center was established in 1988 in Dhaka, the capital city of Bangladesh. It has been implementing a comprehensive program for rheumatic fever and rheumatic heart disease. Outpatient services for rheumatic fever and rheumatic heart disease were formally started in 1990, and have been provided by trained medical officers. They are supported by cardiovascular epidemiologists, cardiologists, and pediatricians. The diagnostic laboratory has been run by microbiologists and clinical pathologists. A computerized database is maintained by the statistics section.
We have examined the database for all subjects who have newly attended in the outpatient clinic in 1991 (July 90 to June 91) through 1997. During this period 2404 subjects have been diagnosed to have rheumatic fever or rheumatic heart disease.
Although the updated Jones criteria 1992 has been recommended by a committee of the American Heart Association3 , its previous version, the revised Jones criteria, has been used in this Center for diagnosis of rheumatic fever4 . Electrocardiography and echocardiography are done whenever carditis is suspected or heart murmur is detected on auscultation. To establish the diagnosis of rheumatic heart disease, chest X-ray and echocardiography are done for all cases. As reported previously5,6 , many patients present with atypical (or milder) manifestations, they are marked as possible rheumatic fever5-7. They are excluded from the current analysis to avoid miss-classification bias5,6 .
The number of subjects presenting for the first time to the outpatient clinic has shown an increasing trend during the observation period (Figure 1), 2063 in 91 and 8428 in 97.
However, the number of subjects diagnosed to have rheumatic fever or rheumatic heart disease has shown just the opposite trend, and has decreased by 63% during a seven-year period: 399 in 91 to 149 in 97 (Figure 2). This time trend graph shows an initial increase between 91 and 92, and thereafter, shows a consistent decline.
An increasing number of subjects presenting to the outpatient clinic indicates an increasing awareness among the people. However, the dramatic rise (Figure 1) may partly be due to unnecessary anxiety prevailing among the parents (although this is a speculation). This unexpected increase in number of subjects has undermined the actual denominator of the study sample.
The encouraging observation, however, is a decreasing trend in rheumatic fever and rheumatic heart disease. If, as we believe, this decline is real, there are several possible explanations. Favorable changes in the socioeconomic conditions and streptococci may be responsible for this declining trend. We speculate that increasing awareness among the people and health professionals also have contributed. However, quantitative assessment of these factors remains difficult.
a) Socioeconomic condition:
Improvement of socioeconomic conditions, diet in particular, was responsible for decrease of rheumatic fever8 even before penicillin became largely available9 . Thereafter, economic factors and penicillin worked synergistically. During 1990s, Bangladesh has experienced a favorable economic development. Figure 1c shows a consistent increasing trend in the per capita gross national income in 91 through 97 (Bangladesh Bureau of Statistics). This contrasts the decreasing trend of rheumatic fever and rheumatic heart disease cases (Figure 3). Nutrition has been identified as one of the most important factors for rheumatic fever in this population5,6,10 . We suppose that nutritional status might have also been improved during this period.
Changes in the prevalence and virulence of the group A beta-hemolytic streptococci have been reported during the period of declining trend in rheumatic fever11 . In this Center also, we have observed some favorable changes. For those who throat cultures were done, 18% tested positive for beta-hemolytic streptococci and among the culture positives 21% had group A in 91. After 93, there have been a steady decline in their isolation rates (unpublished observation). This decline may be due to increasing use of antibiotics such as penicillin12 or some changes in the streptococci themselves11 .
c) Awareness among people:
The Rheumatic Fever Center has been conducting educational programs by using mass media. Additionally, stickers and leaflets have been distributed, and posters have also been displayed. Short films are shown regularly at the waiting room of the outpatient department. Seminars for community leaders, teachers, staffs of non-governmental organization, journalists, and imams (Muslim religious leaders) have been undertaken. As a result, the level of awareness among the general people has been increased. It is perceivable that more parents, nowadays, get their children treated if they (children) get pharyngitis.
d) Awareness among health professionals:
Seminars on prevention of rheumatic fever have been held in most of the medical colleges and many rural health complexes. Doctors, nurses, laboratory technicians and primary health care workers from various parts of the country have been receiving training on rheumatic fever. Training of a large number of health personnel, from both public and private sectors, have improved the referral, diagnostic, therapeutic and prophylactic practice to some extent.
Potential strengths and biases:
Because the Rheumatic Fever Center is a well-equipped multi-speciality unique hospital and services are provided free of charge, it can attract patients from all socioeconomic background. It is implied that the diagnoses done here are relatively reliable. Our large sample size, relative to the contemporary reports from a single population, may partly have answered the question of non-representativeness.
Inaccuracy in the diagnosis of rheumatic fever persists9 , even among trained doctors. Completeness of records depends on those who do the clerking of patients. A study on the basis of hospital cases has a potential for bias, especially in a situation where all cases from the catchment area do not report to the hospital. Many children get treatment outside of hospital, and some milder cases do not come to medical attention at all. The proportion of children treated outside of hospital and the cases without medical attention, may not remain same throughout the study period. About 81% of the subjects presenting to this Center come from urban areas of greater Dhaka6 . Therefore, the situation in the rural and distant urban areas is not reflected in this study.
Among the subjects presenting to the Rheumatic Fever Center, a decreasing trend of rheumatic fever and rheumatic heart disease has been observed. More representative data are needed before the conclusion about Bangladesh is drawn.References
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Rouf Mian Abdur1
Haque K.M.H.S. Sirajul3