ARF recurrences

First known and recurrent acute rheumatic fever (ARF) episodes are preventable (Box 4). After the first known ARF episode, adherence to secondary prophylaxis reduces the likelihood of recurrence.

Among Aboriginal and Torres Strait Islander people in 2015–2019, 604 ARF episodes were recorded as recurrent disease (28%) (Figure 7). Recurrent ARF episodes increased from 90 notifications in 2015 to 138 in 2019 (21 to 30 per 100,000 population, respectively). This is in line with an overall increase in notifications.

Data visualisation - Figure 7: Proportion of ARF diagnoses among Indigenous Australians, by recurrence category, 2019

Box 4: ARF episode category definitions

  • First known episode: A reported ARF episode (definite, probable or possible) in an individual with no known past ARF or RHD.
  • Recurrent episode: A reported ARF episode (definite, probable or possible) in an individual with known past ARF or RHD.

Of the 604 recurrent episodes diagnosed in 2015–2019:

  • 61% were among females—who were more likely to have recurrent episodes (31% compared with 25% among males).
  • the greatest number of recurrences was reported among those aged 5–14.

ARF recurrence rates

The measure of ARF recurrences per 100 patient-years is used to account for the different amounts of time people who have had an ARF episode are at risk of having a recurrent episode. It enables comparison of the total number of days after the first ARF episode a person is at risk of recurrence.

ARF recurrences are most likely to occur in the 12 months following diagnosis of the first known episode of ARF (He et al. 2016). The risk of recurrent ARF gradually decreases with time and recurrences rarely occur more than ten years after the first known episode.

This analysis only includes people who were prescribed secondary prophylaxis in 2019.

In 2019:

  • among 4,580 people who were prescribed BPG, there were 131 reported ARF recurrences (3.2 recurrences per 100 patient-years).
  • most recurrences were in the Northern Territory (79 recurrences).
  • the rate of ARF recurrences per 100 patient-years was highest in Western Australia (4.2) where 20% of people received at least 80% of prescribed BPG doses; the recurrence rate was lowest in South Australia (1.5) where 59% of people received at least 80% of prescribed BPG doses.
  • the rate of recurrence per 100 patient-years generally decreased with age, with the highest risk among those aged 5–14 (4.9), as there were no recurrences in those aged under 5 (Figure 8).

Data visualisation - Figure 8: ARF recurrences per 100 patient-years, among all Australians, by state and territory, 2019

Trend in recurrence rates for Indigenous Australians prescribed BPG

From 2016 to 2019, the ARF recurrence rate per 100 patient-years among Indigenous Australians prescribed BPG decreased from 3.8 to 3.4. The largest change occurred in the Northern Territory, where the rate fell from 5.6 to 3.9 recurrences per 100 patient-years. The recurrence rate for 2015 was excluded due to data quality issues.