Medication Burden and Adherence of Antiretroviral Therapy Among Older People Living with HIV in the Context of Multimorbidity and Polypharmacy: A Multicenter Study

Background: Population aging among people living with HIV (PLWH) has led to a growing burden of multimorbidity and complex medication regimens. However, the relationships between medication-related challenges and antiretroviral therapy (ART) adherence in older PLWH remain insufficiently understood. Methods: A multicenter cross-sectional study was conducted among PLWH aged ≥50 years receiving routine HIV care in Hunan Province, China. Multimorbidity, polypharmacy, potential drug–drug interactions (PDDIs), medication-related burden, and ART adherence were assessed using validated instruments and clinical records. Path analysis was applied to examine hypothesized relationships based on the transactional model of stress and coping. Results: Among 301 participants, 54.2% experienced multimorbidity and 29.2% met criteria for polypharmacy. Medication-related burden was moderate to high. The proposed path model demonstrated good fit. Multimorbidity was positively associated with polypharmacy and PDDIs, both of which contributed to higher medication-related burden. Medication-related burden was the only factor directly associated with lower ART adherence, whereas polypharmacy and PDDIs showed no significant direct effects. Conclusions: Medication-related burden was significantly associated with both clinical complexity indicators and ART adherence among older PLWH. Interventions addressing patients’ subjective treatment burden may be critical for sustaining long-term adherence in aging HIV populations.