Rheumatic Heart Disease Outcomes In Australia: A Linked Data Analysis

Abstract Background Rheumatic Heart Disease (RHD), a chronic acquired heart-valve disease, is a major contributor to morbidity and mortality among Indigenous Australians. We estimate the probability and determinants of progressing from RHD diagnosis to cardiovascular complications/death in the Australian population, addressing methodological shortcomings in existing evidence. Methods This retrospective cohort study used linked RHD register, hospital and death data from five Australian jurisdictions. Cardiovascular complications (heart failure, stroke, endocarditis, atrial fibrillation) and all-cause mortality were measured for people aged <35years diagnosed with first-ever RHD (2010-2018; minimum 8.5year look-back; maximum 8year follow-up). Probability of cardiovascular complications were determined with competing risk of death. Proportional cause-specific hazard regression measured independent predictors of outcomes. Results 1718 RHD cases aged <35years were identified (85% Indigenous, 11% migrant, 63% women, 40% 5-14years, 16% metropolitan). Within 8years, 22% experienced a cardiovascular complication (50% heart failure) and 3.2% died. Age ≥14years (Hazard Ratio,HR:2.0, 95% Confidence Interval,CI:1.4-3.0) and metropolitan residence (HR:3.2, 95%CI:2.0-5.1) were associated with increased risk of cardiovascular complications in cases (relative to < 14years and non-metropolitan). Record of ARF prior to RHD was protective (HR:0.6, 95%CI:0.4-0.8). Conclusions Competing risks methods applied to linked data have provided the most comprehensive multi-jurisdictional estimates of RHD progression to cardiovascular complications/death in Australia. Risk of cardiovascular events was highest in metropolitan areas but clinical history of ARF was associated with reduced risk of progression. Key messages Despite access to the world-class Australian healthcare system, one-fifth of initially uncomplicated RHD diagnoses will progress to one of the complications examined within 8years