The purpose of this study was to determine whether diary-driven adjustment of Medication Event Monitoring System (MEMS) data based on Supporting Information strengthens the relationship between measured antiretroviral medication adherence and plasma HIV viral load (VL).

HIV+ adolescents on antiretroviral treatment were monitored with MEMS for 30 days preceding a VL measurement. The primary outcome was VL ≥ 400 copies/mL. Handwritten diaries were used to comprehensively record deviations from recommended use (bottle opened but dose not taken or bottle not opened and dose taken). Data were adjusted ("cleaned") based on diary events. Data were "capped" at the prescribed number of doses/day. Receiver operator characteristic analysis compared the relationships between (i) raw MEMS data, (ii) diary-cleaned, (iii) capped, or (iv) cleaned and capped MEMS data and VL.

Over 30 days preceding VL measurements, 273 adolescents had 465 diary events. Capping resulted in fewer patients classified as 95% adherent (65.2%) compared with raw data (71.4%), p < 0.001. Adherence was highly associated with VL (OR 1.05, p < 0.001). The area under the receiver operating characteristic curve for continuous adherence compared with VL was 0.89 (95%CI: 0.82-0.95). Neither diary-cleaning, capping, nor cleaning and capping MEMS data significantly altered the association between adherence and VL (p = 0.14, 0.40, and 0.19, respectively).

Medication Event Monitoring System data-cleaning based on diary entries did not affect the adherence-VL relationship.