Self-reported measures of antiretroviral adherence vary greatly in recall time periods and response tasks. To determine which time frame is most accurate, we compared 3-, 7-day, and 1-month self-reports with data from medication event monitoring system (MEMS). To determine which response task is most accurate we compared three different 1-month self-report tasks (frequency, percent, and rating) to MEMS. We analyzed 643 study visits made by 156 participants. Over-reporting (self-report minus MEMS) was significantly less for the 1-month recall period (9%) than for the 3 (17%) or 7-day (14%) periods. Over-reporting was significantly less for the 1-month rating task (3%) than for the 1-month frequency and percent tasks (both 12%). We conclude that 1-month recall periods may be more accurate than 3- or 7-day periods, and that items that ask respondents to rate their adherence may be more accurate than those that ask about frequencies or percents.

Adherence to antiretroviral therapy (ART) represents one of the strongest predictors of progression to AIDS, yet it is difficult for most patients to sustain high levels of adherence. This study compares the efficacy of a personalized cell phone reminder system (ARemind) in enhancing adherence to ART versus a beeper. Twentythree HIV-infected subjects on ART with self-reported adherence less than 85% were randomized to a cellular phone (CP) or beeper (BP). CP subjects received personalized text messages daily; in contrast, BP subjects received a reminder beep at the time of dosing. Interviews were scheduled at weeks 3 and 6. Adherence to ART was measured by self-report (SR, 7-day recall), pill count (PC, past 30 days at baseline, then past 3 weeks), Medication Event Monitoring System (MEMS; cumulatively at 3 and 6 weeks), and via a composite adherence score constructed by combining MEMS, pill count, and self report. A mixed effects model adjusting for baseline adherence was used to compare adherence rates between the intervention groups at 3 and 6 weeks. Nineteen subjects completed all visits, 10 men and 9 females. The mean age was 42.7 AE 6.5 years, 37% of subjects were Caucasian and 89% acquired HIV heterosexually. The average adherence to ART was 79% by SR and 65% by PC at baseline in both arms; over 6 weeks adherence increased and remained significantly higher in the ARemind group using multiple measures of adherence. A larger and longer prospective study is needed to confirm these findings and to better understand optimal reminder messages and user fatigue.