BACKGROUNDResearch is needed to understand the impact of mental health disorders (MHD) on healthcare resource utilization (HCRU) and costs among people with human immunodeficiency virus (PWH).OBJECTIVESExamine the HCRU and cost burden among treatment-naïve PWH with and without MHD initiating single tablet antiretroviral regimens (STRs) and multi-tablet regimens (MTRs).METHODSA retrospective database analysis of the US Medicaid population from Anlitiks' All Payor Claims database between 1 January 2016 and 30 June 2023 was conducted. Treatment-naïve MTR-initiators vs STR-initiators (the index was the first prescription fill claim date) with ≥ 12-months pre- and post-index continuous enrollment and no pre-index HIV-2 diagnosis among PWH/MHD and PWH/no-MHD during 1 January 2017-30 June 2022 were selected. Demographics, clinical characteristics, HCRU and costs between MTR-initiators vs STR-initiators among PWH/MHD and PWH/no-MHD were described using Chi-square tests and Wilcoxon rank-sum or t-tests for categorical and continuous variables, as appropriate. HCRU and costs were examined using multivariable logistic and gamma-log link regression models, controlling for potential confounders.RESULTSMTR-initiators (PWH/MHD: n = 7,874, PWH/no-MHD: n = 3,612) vs. STR-initiators (PWH/MHD: 46,024, PWH/no-MHD: 23,452) were significantly younger (PWH/MHD: 43.6 vs. 47.2 years; PWH/no-MHD: 39.2 vs. 43.3 years) and more likely to be female (PWH/MHD: 46.4% vs. 35.7%; PWH/no-MHD: 42.3% vs 29.7%) in both groups (all p-values < 0.05). MTR-initiators vs. STR-initiators had significantly higher rates of inpatient (IP) hospitalizations (PWH/MHD: 28.9% vs. 27.1%; PWH/no-MHD:13.9% vs. 11.9%) and emergency department (ED) visits (PWH/MHD: 53.3% vs. 49.2%; PWH/no-MHD: 35.2% vs. 31.8%) among both those with and without MHD (all p-values < 0.05). MTR-initiators vs. STR-initiators also had significantly higher adjusted all-cause medical costs (PWH/MHD: $60,228 vs $40,634; PWH/no-MHD: $33,623 vs. $17,996) (all p-values < 0.05).CONCLUSIONSAmong PWH/MHD and PWH/no-MHD, MTR-initiators experienced significantly higher HCRU, and 1.5 times greater costs compared to STR-initiators. In both MTR and STR-initiator groups, the PWH/MHD cohort consistently demonstrated a greater HCRU and cost burden than the PWH/no-MHD.