SMS reminders did not improve PrEP adherence in a randomized controlled trial among young Kenyan women


BACKGROUND: Pre-exposure prophylaxis (PrEP) is highly effective in preventing HIV acquisition. However, adherence among young women has been challenging. SMS reminders have been shown to improve adherence to antiretroviral therapy in some contexts. We present results from a randomized controlled trial of SMS reminders to support PrEP adherence among young women in Kenya.
METHODS: The MPYA (Monitoring PrEP among Young Adult women) study involved 18-24-year-old women with high HIV risk. PrEP adherence was measured over 2 years with a real-time electronic monitor (Wisepill) and pharmacy refill; tenofovir-diphosphate (TFV-DP) levels were determined from dried blood spots for 15% of participants. Participants were randomized 1:1 to SMS reminders versus no reminders. Reminders were initially sent daily, although participants could opt for 'as needed' reminders (if they missed doses). The effect of SMS reminders on adherence was assessed by Poisson models adjusted for study site.
RESULTS: Of 348 women in the study, 173 were assigned daily SMS reminders; 9% opted for 'as needed' reminders. Participants were a median of 21 years old and two-thirds reported condomless sex in the month prior to enrollment. As shown in the figure, adherence decreased over time by both electronic monitoring and pharmacy refill. Correlation between electronically-monitored adherence and TFV-DP levels was high (R2=0.73). Among participants picking up PrEP, electronically-monitored adherence was 26.9% over 24 months and did not differ by arm (27.0% with SMS; 26.7% without SMS; adjusted incidence rate ratio 1.07 [95% CI 0.86, 1.33], p=0.55). No differences were seen between arms when assessing adherence for all participants regardless of PrEP refills, by pharmacy refill data, with only 12 months of follow-up, or by site.

CONCLUSIONS: SMS reminders did not overcome adherence challenges among young Kenyan women taking PrEP over two years. Given the overall low adherence in the trial, additional interventions are needed to support PrEP use in this population.