AbstractBackground: Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) cause significant burdens worldwide. Control strategies depend on secondary prophylaxis (SP) – regular long-term antibiotics - but few studies have examined associations between adherence to SP and outcomes. This thesis aimed to: identify characteristics associated with adherence; determine relationships between adherence and clinical outcomes and recommend appropriate adherence measures.
Methods: Five adherence measures - including percent adherence - were calculated for people living in Australia’s Northern Territory. Clinical outcomes were: ARF recurrence, progression from ARF to RHD, progression to severe RHD, improvement of RHD and death. Logistic regression was used to identify factors associated with adherence. Associations between adherence and outcomes were explored using case-control and case-crossover designs; odds ratios (OR) and confidence intervals (CI) were estimated using logistic regression.
Results: 1,610 people were included in the analysis of factors associated with adherence. Being female, younger and living outside urban areas were associated with higher adherence. Hazardous alcohol use and experience of assault were associated with lower adherence.Increased adherence reduced the likelihood of recurrent ARF: people receiving <80% doses were four times more likely to experience recurrence than those receiving ≥80% (OR: 4.00 [95%CI:1.72 to 9.29]; p=0.001). People with higher adherence were less likely to progress from ARF to RHD, however results were statistically non-significant. Small sample sizes for progression to severe RHD and improvement of RHD precluded statistical analysis. Increased adherence reduced mortality: people receiving <70% of doses were three times more likely to die than those receiving ≥70% (OR: 3.25 [95%CI: 1.58 to 6.68], p=0.001).
Conclusions: These results show that increased adherence to SP is associated with reduced ARF recurrences and mortality, therefore adherence must be optimised. Several adherence measures predicted outcomes; monitoring percent adherence is valuable, and outcomes could be further improved using more accurate measures.
|Date of Award||Oct 2018|
|Supervisor||Anna Ralph (Supervisor), Alan Cass (Supervisor) & Jonathan Carapetis (Supervisor)|