Contemporary Incidence and Prevalence of Rheumatic Fever and Rheumatic Heart Disease in Australia Using Linked Data: The Case for Policy Change

Abstract

Background In 2018, the World Health Organization prioritized control of acute rheumatic fever (ARF) and rheumatic heart disease (RHD), including disease surveillance. We developed strategies for estimating contemporary ARF/RHD incidence and prevalence in Australia (2015-2017) by age group, sex, and region for Indigenous and non-Indigenous Australians based on innovative, direct methods. Methods and Results This population-based study used linked administrative data from 5 Australian jurisdictions. A cohort of ARF (age <45 years) and RHD cases (<55 years) were sourced from jurisdictional ARF/RHD registers, surgical registries, and inpatient data. We developed robust methods for epidemiologic case ascertainment for ARF/RHD. We calculated age-specific and age-standardized incidence and prevalence. Age-standardized rate and prevalence ratios compared disease burden between demographic subgroups. Of 1425 ARF episodes, 72.1% were first-ever, 88.8% in Indigenous people and 78.6% were aged <25 years. The age-standardized ARF first-ever rates were 71.9 and 0.60/100 000 for Indigenous and non-Indigenous populations, respectively (age-standardized rate ratio=124.1; 95% CI, 105.2-146.3). The 2017 Global Burden of Disease RHD prevalent counts for Australia (<55 years) underestimate the burden (1518 versus 6156 Australia-wide extrapolated from our study). The Indigenous age-standardized RHD prevalence (666.3/100 000) was 61.4 times higher (95% CI, 59.3-63.5) than non-Indigenous (10.9/100 000). Female RHD prevalence was double that in males. Regions in northern Australia had the highest rates. Conclusions This study provides the most accurate estimates to date of Australian ARF and RHD rates. The high Indigenous burden necessitates urgent government action. Findings suggest RHD may be underestimated in many high-resource settings. The linked data methods outlined here have potential for global applicability.

Keywords: Australia; epidemiology; ethnic; inequalities; linked data; rheumatic heart disease.

Figure 1. Percentage of prevalent RHD cases in mid‐2017 with a history of complications of RHD and concurrent RHD and pregnancy, by age group and Indigenous status.

RHD indicates rheumatic heart disease.

Figure 2. Age‐specific incidence of ARF and prevalence of RHD in 5 Australian jurisdictions, by Indigenous status, 2015 to 2017.

ARF total includes first‐ever episodes of ARF plus ARF recurrences. Severe RHD includes RHD cases who were recorded as having been in heart failure, received at least 1 cardiac valvular intervention or were recorded on RHD register as being severe. ARF or RHD includes any live person with a history of either ARF or RHD. ARF indicates acute rheumatic fever; and RHD, rheumatic heart disease.

Figure 3. Sex differentials in the age‐standardized incidence and prevalence of ARF and RHD in 5 Australian jurisdictions, by Indigenous status.

ARF total includes first‐ever episodes of ARF plus ARF recurrences. Severe RHD includes RHD cases who were recorded as having been in heart failure, received at least 1 cardiac valvular intervention or were recorded on RHD register as being severe. ARF or RHD includes any live person with a history of either ARF or RHD. ARF indicates acute rheumatic fever; PR, prevalence ratio; RHD, rheumatic heart disease; and RR, rate ratio.

Figure 4. Total population (A) and Indigenous (B) age‐standardized prevalence (per 100 000) of acute rheumatic fever or rheumatic heart disease in five Australian jurisdictions, by Indigenous Region Categories.

Within jurisdictional geographic regions are aggregations of 33 separate Indigenous Regions provided by the Australian Bureau of Statistics (see Data S1). NSW indicates New South Wales; NT, Northern Territory; QLD, Queensland; SA, South Australia; TAS Tasmania; VIC, Victoria; and WA, Western Australia.