Abstract 9168: Echocardiography-Based Screening for Rheumatic Heart Disease: A Sensitive and Cost-effective Way to Reduce Disease Burden in the Developing World

Abstract

Introduction: Early detection and prophylaxis of rheumatic heart disease (RHD) can prevent devastating sequlae. Echocardiography (echo)-based screening improves detection of RHD in endemic regions, but the best protocol to maximize case detection and minimize over-diagnosis is unclear. The recent WHO/NIH 2006 guidelines have yet to be assessed in a large-scale prevalence study. We used these guidelines and identified risk factors for occult RHD in a large cohort of Ugandan school children. We tested two hypotheses: echo screening for RHD is inexpensive and more sensitive than auscultation and laboratory testing; and RHD is more prevalent in lower socioeconomic groups. Methods: Auscultation and portable ultrasound were used to screen students, ages 5 to 16, from randomly selected schools in Kampala, Uganda. Positive cases followed up at Kampala's main referral hospital. Studies were blindly reviewed by three independent cardiologists. Categories for disease likelihood - definite, probable, and possible - were assigned based on the 2006 guidelines. Detection rates by auscultation and echo imaging were compared. ASO titers and markers of inflammation (ESR/CRP) were obtained on follow-up cases. The impact of socioeconomic status was examined. Results: Screening of 4869 of 5006 (97%) eligible students occurred in 6 schools over a 4-month period. Screening was abnormal in 130 children. On follow-up, 18 had congenital heart disease, 40 were normal, and 72 had possible, probable, or definite RHD. Echo detected 3 times as many cases of RHD than auscultation alone: 72 (1.5%) vs.23 (0.5%), p<0.001. Children with RHD were older (10.1 yr vs. 9.3 yr, p=0.002). Most cases (98%) involved only the mitral valve. Children from lower socioeconomic schools had RHD more frequently (2.7% vs. 1.4%, p=0.036) and had more advanced disease (64% vs. 26%, p<0.001). Labs had no significance. Each study cost $0.18 (echo machine, nursing, and transportation). Conclusions: This is the largest single-country childhood RHD prevalence study to date. Our data support the inclusion of echo in screening protocols and identify lower socioeconomic groups as the most vulnerable. Efforts should be made to promote more widespread use of echo screening, which can be done for only pennies a student.