Echocardiographic Screening for Rheumatic Heart Disease in High and Low Risk Australian Children
What is the echocardiographic prevalence of rheumatic heart disease (RHD) in high-risk Indigenous Australian children compared to Australian children at low risk for RHD?
Portable echocardiography was performed on high-risk Indigenous children ages 5-15 years living in remote communities of northern Australia. A comparison group of low-risk, non-Indigenous children living in urban centers also was screened. Echocardiograms were reported in a standardized, blinded fashion. RHD was diagnosed using recently published World Heart Federation (WHF) criteria.
Of 3,946 high-risk children, 34 met WHF criteria for definite RHD (prevalence 8.6 per 1,000; 95% confidence interval [CI], 6.0-12.0) and 66 for borderline RHD (prevalence 16.7 per 1,000; 95% CI, 13.0-21.2). Of 1,053 low-risk children, none met criteria for definite RHD, and five met criteria for borderline RHD. High-risk children were more likely to have definite or borderline RHD than low-risk children (adjusted odds ratio, 5.7; 95% CI, 2.3-14.1; p < 0.001).
The prevalence of definite RHD in high-risk Indigenous Australian children approximates what was expected in this population, and no definite RHD was identified in the low-risk group. This study suggests that definite RHD, as defined by the WHF criteria, likely represents true disease. Borderline RHD was identified in children at both low and high risk, highlighting the need for longitudinal studies to evaluate the clinical significance of this finding.
RHD remains a source of substantial morbidity and mortality in developing countries. Efforts to decrease the incidence of rheumatic fever (RF) and the severity of RHD involve reduced exposure to group A streptococcus (sometimes termed primordial prevention), appropriate treatment of streptococcal pharyngitis (primary prevention), and prevention of RF recurrence (secondary prophylaxis). Because many cases of RF are subclinical, accurate detection of existing RHD is of importance for appropriate secondary prevention. Probably approximately 90% of cases of RHD are silent on physical examination and detectable only by echocardiography. In 2012, the WHF published echo/Doppler criteria for the diagnosis of RHD, establishing diagnoses of definite RHD and borderline RHD, and attempting in part to differentiate mild RHD from normal findings (Reméyni B, et al. Nat Rev Cardiol 2012;9:297-309). The present study confirms that the WHF criteria used for the diagnosis of definite RF appear valid. It is more difficult to judge the WHF criteria for borderline RHD, with no ‘gold standard’ other than the eventual progression and development of clinical valve disease.
Keywords: Child, Pharyngitis, Rheumatic Fever, Rheumatic Heart Disease, Secondary Prevention, Australia, Streptococcus pyogenes, Physical Examination, Primary Prevention, Echocardiography
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