(253) Treatment switch among United States Medicare beneficiaries with human immunodeficiency virus

Background: : People with HIV (PWH) enrolled in Medicare health insurance often have a higher prevalence of comorbidities like mental health and substance use disorder, which can negatively impact adherence and persistence.

Objective: : Describe treatment switch by HIV antiretroviral therapy (ART) in PWH insured by Medicare.

Methods: : This retrospective cohort study included treatment-experienced PWH aged ≥18 years who initiated ART between January 2018 and September 2022 and were insured by Medicare fee-for-service or Medicare Advantage in the United States. The index date was the earliest initiation date of the following regimens: B/F/TAF, DTG/3TC, DTG/ABC/3TC, or DTG+FTC/TAF or DTG+FTC/TDF (multi-tablet regimens [MTRs]). PWH were followed from index date until switch (defined as starting a new regimen within 90 days of ending the index regimen), discontinuation, death, end of Medicare enrolment, or December 2022. Time-to-switch was evaluated using Kaplan-Meier curves. Adjusted hazard ratios (HRs) of switch were estimated using Cox models with inverse probability treatment weighting to account for baseline characteristics, overall and for a subgroup with mental health or substance use disorders.

Results: : Among 30,205 PWH, average age ranged from 54.1 (MTRs) to 61.7 (DTG/3TC) years and 71.6% were male. Demographic characteristics differed by index treatment, with those in the DTG/3TC group having a higher prevalence of being Non-Hispanic White and lower prevalence of Medicaid eligibility and Part D low-income subsidy than PWH taking other ARTs, particularly MTRs.
In unadjusted analyses, treatment switch was lowest among PWH receiving B/F/TAF (log-rank test P< 0.0001), both overall and in the mental health/substance use disorders subgroup. In adjusted analyses, the HR of switch was 1.28 (95% CI: 1.13, 1.44) for DTG/3TC, 2.33 (2.15, 2.52) for DTG/ABC/3TC, and 4.75 (4.08, 5.55) for MTRs compared to B/F/TAF overall, with similar results in the mental health/substance use disorders subgroup (all P< 0.05).

Conclusions: : Among Medicare PWH, those taking B/F/TAF had lower likelihood of switch and longer time to switch than PWH taking other ART regimens, complementing persistence data.

Sponsorship:: Gilead Sciences, Inc.