We report the reliability, validity, and feasibility of self-performed picture pill count (PPC) as an adherence measure that was used in a randomized trial with HIV positive people living in rural Georgia. The first 61 (of 149) participants conducted an additional PPC 1-2 days after baseline. Reliability, measured by a PPC scoring instrument, analyzed participants' ability to reproduce high quality pill count photographs free from artifact or blurring that could hamper accurate visualization of the pills and bottle labels. Except for label blur, baseline photographs (performed with coaching by study staff) and independently performed post-baseline photographs were rated as acceptable quality (> 93%). Label blur significantly worsened between the baseline and post-baseline scoring (93% vs 80%, p = 0.039), possibly indicating that participants required more education to ensure readability. Validity was determined by comparing the number of pills entered into the PC survey with the number of pills in the texted PPC; 77.5% of participants had perfectly matched pill counts (r = 0.690, p < 0.001). We found PCC to be a reliable and valid method of measuring adherence. The high rate of participant satisfaction underscores its feasibility. It provides an innovative alternative to other more invasive and labor intensive methods of measuring adherence using pill counts.
Keywords: Adherence; Antiretroviral therapy; HIV/AIDS; Pill counts; Rural health.