P4335The incidence of acute rheumatic fever in indigenous adults in the Northern Territory, South Australia and Western Australia

Abstract

Abstract Background Worldwide, knowledge of the contemporary incidence of acute rheumatic fever (ARF) in Indigenous adult populations is limited, with little understanding of patterns of ARF recurrence according to age and geographical location. This has created uncertainty in the development of rheumatic heart disease (RHD) guidelines surrounding the appropriate duration of antibiotic prophylaxis for these patients. Purpose This study aimed to describe the incidence rates of ARF in Indigenous Australian adults, analyse patterns of recurrence according to sex, age and geographical location, and assess adherence to secondary prophylaxis. Methods ARF episodes in Indigenous adults, aged 18 years and older, recorded within three Australian jurisdictions (Northern Territory, South Australia and Western Australia) ARF registers, diagnosed between 2007 to 2017, were included. Poisson and negative binomial regression were used to estimate incidence rate ratios (IRR) and 95% confidence intervals (CI) for first and recurrent episodes according to age, sex and remoteness. Adherence rates to secondary prophylaxis was described in the 12 months preceding recurrent ARF episodes in the Northern Territory. Results 481 episodes were analysed. The incidence of ARF episodes in these jurisdictions from 2007 to 2017 was relatively constant. The overwhelming burden of disease occurred in remote areas (105 episodes per 100,000 people). An increased rate occurred in females (IRR 2.34, 95% CI 1.81–3.03). The 18–24 year olds had the highest incidence rates (115 episodes per 100,000 people). High rates of recurrence were also observed in those aged 25–34 years (96 episodes per 100,000 people). Adherence to secondary prophylaxis in those having a recurrent episode was only achieved in 10% of cases. Conclusions The incidence of ARF remains very high amongst adult Indigenous Australians. Adherence to secondary prophylaxis continues to play a role in recurrent episodes. RHD guidelines should take into account remoteness as a significant risk factor when deciding the duration of secondary prophylaxis.