The epidemiology of acute rheumatic fever and rheumatic heart disease in Queensland, 2017-2021: a population-level cohort study using linked administrative data.

Objectives: To determine the incidence and prevalence of acute rheumatic fever (ARF) and rheumatic heart disease (RHD) in Queensland during the period 2017-2021.

Study design: Population-level retrospective cohort study using linked administrative data.

Setting, participants: Queensland residents aged younger than 45 years for ARF and younger than 55 years for RHD, identified from hospital, emergency department, death and Queensland RHD Register records for the period 1 January 2017 to 31 December 2021.

Main outcome measures: Age-specific and age-standardised incidence and prevalence of ARF and RHD; and age-standardised incidence and prevalence ratios comparing Indigenous and non-Indigenous populations.

Results: 736 ARF episodes occurred among 670 people (395 [54%] female participants; 609 [83%] Indigenous). Of 4519 prevalent RHD cases aged < 55 years who were alive on 1 July 2021, 2655 (59%) were female, 2169 (48%) were Indigenous, and 1846 (41%) had severe disease. Previous ARF was recorded for 362 cases (8%). Among RHD cases aged younger than 25 years, 633 of 790 Indigenous individuals (80%) and 133 of 408 non-Indigenous individuals (33%) had RHD Register records. Indigenous age-standardised incidence (< 45 years) was 60.2 times higher (95% CI, 55.6-64.2) than non-Indigenous incidence for first ever ARF, 68.6 times higher (95% CI, 62.3-72.5) for total ARF, and 18.9 times higher (95% CI, 13.5-24.1) for RHD. For Indigenous people aged < 55 years, prevalence was 22.6 times higher (95% CI, 16.2-27.3) for ARF/RHD, 18.4 times higher (95% CI, 12.9-24.1) for RHD, and 12.1 times higher (95% CI, 8.3-15.9) for severe RHD. The overall burden of ARF and RHD was highest in northern Queensland health districts, whereas cases in the non-Indigenous population were concentrated in metropolitan south-east Queensland.

Conclusions: The vast disparity in ARF and RHD burden between Indigenous and non-Indigenous Queenslanders indicates an urgent need for targeted, community-led prevention strategies. Under-representation of non-Indigenous youth in the RHD Register suggests improved clinical awareness and reporting is needed. Further investigation is warranted to inform equitable responses.