Epidemiological trends of RF/RHD in school children of Shimla in north India

BACKGROUND & OBJECTIVES: There are no active surveillance studies reported from South East Asian Region to document the impact of change in socio-economic state on the prevalence of rheumatic fever/rheumatic heart disease (RF/RHD) in children. Therefore, we conducted a study to determine the epidemiological trends of RF/RHD in school children of Shimla city and adjoining suburbs in north India and its association with change in socio-economic status. METHODS: Active surveillance studies were conducted in 2007-2008 in urban and rural areas of Shimla, and 15145 school children, aged 5-15 yr were included and identical screening methodology as used in earlier similar survey conducted in 1992-1993 was used. The study samples were selected from schools of Shimla city and adjoining rural areas by multistage stratified cluster sampling method in both survey studies. After a relevant history and clinical examination by trained doctor, echocardiographic evaluation of suspected cases was done. An updated Jones (1992) criterion was used to diagnose cases of acute rheumatic fever (ARF) and identical 2D-morphological and Doppler criteria were used to diagnose RHD in both the survey studies. The socio-economic and healthcare transitions of study area were assessed during the study interval period. RESULTS: Time trends of prevalence of RF/RHD revealed about five-fold decline from 2.98/1000 (95% C.I. 2.24-3.72/1000) in 1992-1993 to 0.59/1000 (95% C.I. 0.22-0.96/1000) in 2007-2008. (P<0.0001). While the prevalence of ARF and RHD with recurrence of activity was 0.176/1000 and 0.53/1000, respectively in 1992-1993, no case of RF was recorded in 2007-2008 study. Prevalence of RF/RHD was about two- fold higher in rural school children than urban school children in both the survey studies (4.42/1000 vs. 2.12/1000) and (0.88/1000 vs. 0.41/1000), respectively. The indices of socio-economic development revealed substantial improvement during this interim period. INTERPRETATION & CONCLUSIONS: The prevalence of RF/RHD has declined by five-fold over last 15 yr and appears to be largely contributed by improvement in socio-economic status and healthcare delivery systems. However, the role of change in the rheumatogenic characteristics of the streptococcal stains in the study area over a period of time in decline of RF/RHD cannot be ruled out. Policy interventions to improve living standards, existing healthcare facilities and awareness can go a long way in reducing the morbidity and mortality burden of RF/RHD in developing countries.