BACKGROUND: Polypharmacy (use of ≥ 5 medications) increases the risk of drug-drug interactions and can lead to negative health outcomes. This study aimed to review the medications of people living with HIV (PLWH) and HIV negative controls in the POPPY study and evaluate the frequency of polypharmacy and potential drug-drug interactions (PDDI). METHODS: Potential drug-drug interactions between non-antiretroviral (ARV) drugs were analysed using the Lexicomp® database, and PDDI between non-ARV and ARV drugs using the Liverpool drug interaction database. Between-group differences were assessed using Chi-squared, Mann-Whitney U and Kruskal Wallis tests. RESULTS: This analysis included 698 PLWH ≥50 years, 374 PLWH <50 years and 304 HIV-negative controls ≥50 years. The prevalence of polypharmacy was 65.8% in older PLWH, 48.1% in younger PLWH, and 13.2% in the HIV negative group. When ARVs were excluded 29.8% of older PLWH and 14.2% of younger PLWH had polypharmacy. The prevalence of ≥1 PDDI involving non-ARV drugs was 36.1%, 20.3% and 16.4% respectively in older PLWH, younger PLWH and HIV negative controls. In PLWH the prevalence of ≥1 PDDI involving ARV and non-ARV drugs was 57.3% in older PLWH and 32.4% in younger PLWH. CONCLUSIONS: Polypharmacy and PDDI involving non-ARV/ARV drugs and non-ARV/non-ARV drugs were common among older PLWH, highlighting the need for increased awareness and additional research on all types of PDDI
