Parallel declines in antiretroviral therapy adherence by dried blood spot and electronic monitoring in Cape Town, South Africa.

Among 250 adults with HIV (median age 34 years, IQR 27-42; 78% women), tenofovir diphosphate (TFV-DP) concentrations in dried blood spots and electronic adherence declined over 12 months. Mean TFV-DP fell from 1219 to 939 fmol/punch in men and 1148 to 894 in women, while electronic adherence declined from 65 to 49% in men and from 62 to 52% in women. Visit predicted declines in TFV-DP (F = 7.17, P < 0.001) and electronic adherence (F = 2.57, P = 0.003).