[Antiretroviral adherence evaluation in México: 4-day adherence recall vs. the adherence index].

Compare two indirect methods for measuring adherence to antiretrovirals (ARV) for people living with HIV (PLWHA) in México.Sectional study of direct interviews with patients selected from a representative sample of PLWHA care units in México. We estimated in 2,054 patients the adherence of four days as the measurement used traditionally in México and the adherence index as a measurement that is reported more correlated with biological measurements. For the latter, use was made of all items on the questionnaire AIDS Clinical Group (ACTG) (adherence rate, monitoring the schedule and special instructions, and time since the last time you stopped taking ARV). In both cases, was considered adequate adhesion values ≥ 95%.The adherence of four days identifies 13.2% (n = 271) of patients with levels less than the recommended (8.3% of 56-94% and 4.9% of 0- 55%) according to the index, the percentage of patients with lower levels of adherence to recommended was 45.0% (n = 924) (40.5% of 56-94%, 4.5% of 0-55%).The estimate of adherence of 4 days may be underestimating significantly the adherence problem in PLWHA in Mexico, according to the comparison with the calculated value. Considering the values reported by the index, it is necessary to strengthen strategies to promote adherence to treatment and that a high percentage of patients has levels of adherence that jeopardize the effectiveness of treatment.