Abstract
Background
Timely, accurate adherence data may support oral PrEP success and inform prophylaxis choice. We evaluated an FDA-approved digital health feedback system (DHFS) with ingestible-sensor-enabled (IS) tenofovir-disoproxil-fumarate plus emtricitabine (Truvada®) in persons starting oral PrEP.
Methods
HIV-negative adults were prescribed IS-Truvada® with DHFS for 12 weeks to observe medication taking behavior. Baseline demographics, urine toxicology and self-report questionnaires were obtained. Positive detection accuracy and adverse events were computed as percentages, with Kaplan Meier Estimate for persistence-of-use. In participants persisting ≥ 28 days, adherence patterns (taking and timing) were analyzed and mixed-effects logistic regression modelled characteristics associated with treatment adherence.
Results
Seventy-one participants enrolled, mean age 37.6 years (range 18-69), 90.1% male, 77.5% white, 33.8% Hispanic, 95.8% housed and 74.6% employed. Sixty-three participants (88.7%) persisted ≥28 days, generating 4987 observation days, average 79.2 (29-105). Total confirmed doses were 86.2% (CI
95 82.5, 89.4), decreasing over time, OR 0.899 (CI
95 0.876, 0.923) per week, p < 0.001; 79.4% (CI
95 66.7%, 87.3%) of participants had ≥80% adherence. Pattern analysis showed days without confirmed doses clustered (p = 0.003); regular dose timing was higher among participants with ≥80% confirmed doses (0.828, CI
95 0.796 to 0.859) than among those with <80% (0.542, CI
95 0.405 to 0.679) p < 0.001. In multi-predictor models, better adherence was associated with older age, OR 1.060 (CI
95 1.033, 1.091) per year, p < 0.001; negative vs positive methamphetamine screen, OR 5.051 (CI
95 2.252, 11.494), p < 0.001.
Conclusions
DHFS with IS-Truvada® distinguished adherent persons from those potentially at risk of prophylactic failure. Ongoing methamphetamine substance use may impact oral PrEP success.
