Sub-clinical rheumatic heart disease (RHD) detected by hand-held echocardiogram in children participating in a school-based RHD prevention program in Tanzania

BACKGROUND: Rheumatic Heart Disease (RHD) continues to cause suffering and premature deaths in many sub-Saharan Africa (SSA) countries, where the disease is still endemic. RHD is largely preventable and determining its community burden is an important critical step in any RHD prevention program. METHODS: We conducted a cross-sectional study of 5–16 years old pupils from 11 primary schools participating in an RHD prevention program in 4 districts in Tanzania, between 2018 and 2019. At the school, all children were invited to participate after receiving consent from their parents/guardians. Participating children filled a questionnaire and were auscultated for cardiac murmurs. Echocardiographic screening was done by two experienced cardiologists, using a hand-held machine (V-Scan, GE®). All positive screening tests were stored for further examination by the same two cardiologists to reach to a consensus of definite, borderline or no RHD, using a modified World Heart Federation (WHF) criterion. RESULTS: Of the 6895 children invited, 4738 (68.7%) were screened and 4436 (64.3%) had complete data. The mean (SD) age was 10.04 (2.43) years, and 2422 (54.6%) were girls. Fifty three (1.2%) children were found to have a murmur. The proportion of children with trace or mild valvular regurgitation, sub-valvular/chordal thickening and valvular thickening/deformity were 8.3%, 1.3%, and 1.0%, respectively. Sub-clinical RHD was found in 95 children (59 definite and 36 borderline), giving a prevalence of 2.1%, [95% CI 1.7% – 2.6%]. Sub-clinical RHD was independently associated with female sex (aOR 1.83, 95% CI 1.18–2.85, p = 0.007), older age groups (aOR 1.73, 95% CI 1.10–2.72, p = 0.018 for age group 11–14 years; and aOR 3.02 95% CI 1.01–9.05, p = 0.048 for age group 15–16 years), as well as presence of a cardiac murmur, aOR 5.63 95% CI 2.31–13.69, p < 0.0001. None of the studied socio- or economic factors was associated with the presence of sub-clinical RHD in this study. CONCLUSION: The prevalence of sub-clinical RHD among primary school children in Tanzania is 2.1%, similar to previous reports in SSA. Efforts to prevent and control RHD in our communities are highly warranted.