Background and Importance The goal of antiretroviral therapy (ART) is virological suppression since subtherapeutic levels of antiretrovirals can lead to development of resistance. A correct adherence treatment is crucial to achieve that issue.

Aim and Objectives To identify the degree of adherence to ART in HIV-positive patients and analyse whether it is related to virological results and the type of ART used.

Material and Methods Retrospective observational study of HIV patients attended at our Pharmacy Outpatient Unit during the year 2022. The following variables were collected: sex, age, viral load (VL), type of ART (drugs, number of tablets), excluding those in treatment less of 6 months.

Adherence was estimated with the indirect method of the medication possession ratio (MPR), defined as the percentage of days covered with the dispensed medication compared to total days with the prescribed medication x 100. Good adherence was defined as an MPR 95–100%, intermediate adherence: MPR 80–95% and poor adherence: MPR<80%.

Results 53 patients were eligible for the study (69.8% men with a mean age of 49.2±10.3 years and 50.9±9.4 years in women), of which 84.9% received triple therapy, 11.3% double therapy and 3.8% monotherapy.

The overall mean adherence was 95.1±7.2% (95.7% in women and 94.9% in men), of which 67.9% had good adherence (52±10.2 years), 22.6% intermediate adherence (47±7.9 years) and 9.4% poor adherence(42±5.9 years).

VL was undetectable in 84.9% of cases (mean adherence 95.9%) and unknown in 9.4% during the study year. Only three patients (5.7%) were detectable, two with good adherence and one with intermediate adherence.

Regarding the number of daily tablets, adherence was good in patients who took 1, 2 and 3 tablets daily (95.3±7.3%) and intermediate in those who took 4 tablets daily (90.7±8.7%).

Conclusion and Relevance Most patients in our study have good adherence and it is higher in older patients and the less tablets daily they take. No relationship was found between patient gender and adherence. The cases of detectable VL were not associated with poor adherence to ART, which could be due to patient resistance or limitations of the adherence measurement method.

Conflict of Interest No conflict of interest.