ObjectivesThis study aimed to assess and compare the occurrence of 3-HIT in people living with HIV (PLWH) and seronegative patients. Additionally, the study investigated whether HIV infection could serve as a predictor of the presence of 3-HIT.MethodsA cross-sectional study was conducted between December 2022 and January 2023 to compare PLWH with a group of seronegative patients with chronic diseases attending an outpatient hospital pharmacy service. The 3-HIT concept encompasses the simultaneous presence of non-adherence to concomitant treatment (NAC), drug–drug interactions (DDIs), and high pharmacotherapeutic complexity in polymedicated patients. The assessment of 3-HIT compliance included NAC, evaluated using both the Morisky-Green questionnaire and electronic pharmacy dispensing records. DDIs were analysed using the Liverpool University and Micromedex databases. Pharmacotherapeutic complexity was measured using the Medication Regimen Complexity Index (MRCI) tool. Logistic regression analysis was performed to identify independent factors related to 3-HIT. Additionally, an explanatory logistic model was created to investigate whether HIV infection, along with other adjustment variables, could predict compliance with the 3-HIT concept.ResultsThe study included 145 patients: 75 PLWH and 70 seronegative patients. The median age was 40 versus 39 years, respectively (p=0.22). Seronegative patients exhibited a higher prevalence of NAC (p<0.01). HIV infection was identified as a protective factor in the context of DDIs (p<0.01). Male sex (p<0.01) and age (p=0.01) were identified as being associated with an MRCI ≥11.25 points. A higher prevalence of 3-HIT was observed in seronegative patients (18.7% vs 48.6%, p<0.01). However, the developed regression model identified HIV infection as a risk factor associated with an increased likelihood of 3-HIT (OR 4.00, 95% CI 1.88 to 8.52, p<0.01).ConclusionsThe 3-HIT concept exhibited a high prevalence among seronegative patients with chronic diseases, with HIV infection identified as a predicted risk factor for NAC and the development of 3-HIT.