Prevalence and risk factors for Subclinical Rheumatic Heart Disease among primary school children in Dar es Salaam, Tanzania: a community based cross-sectional study

Abstract

Background Rheumatic heart disease (RHD) is the most common acquired heart disease occurring in children and adolescents. RHD is associated with significant morbidity and mortality particularly in low and middle- income countries (LMICs) where the burden is estimated to be higher compared to high income countries. Subclinical RHD is the presence of valvular lesion diagnosed by echocardiography in a person with no clinical manifestation of RHD. This study aimed at determining the prevalence, types and factors associated with subclinical RHD among primary school children in Dar Es Salaam, Tanzania. Methods A descriptive community-based cross-sectional study was conducted in primary school children from February to May 2019. A standardized structured questionnaire was used to collect demographic characteristics, history of upper respiratory tract infections (URTIs), anthropometric measurements, and chest auscultation findings. Moreover echocardiographic screening was done to all children recruited into the study. World Heart Federation echocardiographic classification was used to define the types and prevalence of subclinical RHD. Results A total of 949 primary school children were enrolled with females being predominant (57.1%). The prevalence of subclinical RHD was 34 per 1000. All the participants had mitral valve disease only whereby 17 had definite disease and 15 had a borderline disease. The associated factors for subclinical RHD were older age of more than 9 years (OR 10.8, 95% CI 1.4–82.2, P = 0.02) having three or more episodes of URTI in previous six months (OR 21, 95% CI 9.6–46, P = 0.00) and poor hygiene (OR 3, 95% CI 1.3–6.8, P = 0.009). Conclusion Subclinical RHD as detected by echocardiographic screening is prevalent in primary school children, uniformly affects the mitral valve, and is associated with potentially modifiable risk factors. Children with a history of more than three episodes of URTI in six months represents a high-risk population that should be targeted for RHD screening.

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

“…In this study, female children were 83% more likely to have a positive screening test for RHD when compared to male children. This finding is similar to many previous studies [ 9 – 11 , 13 , 14 , 35 ]. The reasons of higher RHD among females are not well understood [ 35 – 37 ], although it is generally known that most of autoimmune diseases affect females more than males [ 38 ].…”

“…We found RHD to be more likely diagnosed in the older age children as previously reported [ 9 , 11 , 13 , 14 ]. This is an expected occurrence as in these older children several episodes of ARF may have occurred, therefore the fibrosis, valve deformity and valve dysfunction accompanying RHD is more likely to be detected at this age [ 19 ].…”

“…Although the schools we studied were either semi-urban or rural located, we did not find significant different prevalence of RHD between these schools, indicating similar occurrence of the disease burden in this age group, independent of location. In fact, in a similar screening survey involving school children in Dar es Salaam (the most urbanized city in Tanzania), the prevalence of sub-clinical RHD was higher (3.4%) than the current study [ 14 ]. Moreover, our results showed no difference in prevalence between Manyara and Pwani Regions.…”

“…This study is the largest on RHD prevalence in Tanzania and is among the few studies that estimated the prevalence of RHD in East Africa [ 11 , 12 , 14 ]. Being part of an on-going program [ 43 ], this study is unique due to the fact that it will generate longitudinal data.…”

Focused cardiac ultrasound in pregnancy

“…These parameters may be fulfilled in many LMICs which still have a significant presence of rheumatic heart disease. [36][37][38] Of great concern is the late discovery of heart disease in these patients. For example, in the study from Kenya, 22.6% of patients with rheumatic disease in pregnancy were first diagnosed in the third trimester or in labor and 17% after delivery.…”