Efficacy of an incentive intervention on secondary prophylaxis for young people with rheumatic fever: a multiple baseline study

BACKGROUND: Acute rheumatic fever in New Zealand persists and is a barometer of equity as its burden almost exclusively falls on Māori and Pacific Island populations. The primary objective of this study is to determine whether an incentive programme will result in increased secondary prophylaxis injections over a one-year period compared to a baseline period prior to the intervention. METHODS: The evaluation used a multiple baseline study to determine whether an incentive consisting of a mobile phone and monthly “top-up” (for data/calls) resulted in increased injections, increased texts/calls with nurses, reduced number of visits to get a successful injection, less medicine wasted, and increased nurse satisfaction. Participants were 77 young people (aged 14–21) on an acute rheumatic fever registry in Waikato region, New Zealand classified as either fully adherent (all injections received and no more than one late) or partially adherent based on injections at baseline. RESULTS: There was a sharp increase in injections for intermittent patients post-intervention and then a slight decrease overtime, while fully adherent patients maintained their high rate of injections (p = .003). A similar pattern for nurse satisfaction emerged (p = .001). The number of calls/texts increased for all patients (p = .003). The number of visits went down for partially adherent patients and up for fully adherent patients (p = .012). The overall incremental cost-effectiveness was $989 per extra successful injection although costs increased sharply toward the end of the intervention. CONCLUSIONS: Incentivising secondary prophylaxis appears to have a strong impact for partially adherent patients, particularly during the early periods following the initiation of the intervention. Enhancing communication with patients who returned to care may result in more sustainable adherence. TRIAL REGISTRATION: Retrospectively registered: Australia New Zealand Clinical Trials Registry ACTRN12618001150235, 12 July 2018.