(252) Treatment switch among Medicare-insured people with human immunodeficiency virus and gaps in care

Background: : People with HIV (PWH) often face challenges with adherence and persistence to antiretroviral therapy (ART), impacting long-term treatment success.

Objective: : The purpose of this study was to describe treatment switch by ART regimen in PWH insured by Medicare who have significant gaps in care prior to resuming ART and those with low adherence while on therapy.

Methods: : This retrospective cohort study extracted data for Treatment-experienced (TE) PWH age 18 or older who initiated ART between 1/1/2018 and 9/30/2022 and were insured by Medicare fee-for-service or Medicare Advantage. Index date was defined as the earliest date of initiating ART with one of the following: BIC/FTC/TAF, DTG/3TC, DTG/ABC/3TC, or DTG+FTC/TAF or DTG+FTC/TDF (MTRs). We examined two study cohorts: (1) TE PWH with ≥ 90-day gap in treatment in the 6 months prior to initiating the index regimen and (2) TE PWH with low adherence on the index therapy measured by proportion of days covered (PDC) < 85% in the first year of follow-up. PWH were followed from index date until switch, censoring at discontinuation, death, end of Medicare enrollment, or 12/31/2022. Switch was defined as starting a new ART regimen within 90 days of the end of the last fill for the index ART. Treatment persistence until switch was evaluated using Kaplan-Meier curves and the log-rank test. Adjusted hazard ratios (HRs [95% CI]) were calculated to assess risk of switch after inverse propensity score treatment weighting.

Results: : Among 30,205 TE PWH, 7,227 initiated ART after a gap of ≥ 90 days; and 6,140 had a PDC < 85% while on the index regimen. Both study cohorts showed differences in treatment switch by ART, with PWH initiating BIC/FTC/TAF having the lowest likelihood of switch compared to other regimens (log-rank test p< 0.0001). Among PWH with a ≥90-day gap prior to initiating ART, adjusted HRs were 1.65 (1.21, 2.24) for DTG/3TC, 4.05 (3.07, 5.34) for DTG/ABC/3TC, and 7.83 (5.47, 11.22) for MTRs compared to BIC/FTC/TAF. Among the PDC < 85% group, adjusted HRs for switch were 1.65 (1.08, 2.53) for DTG/3TC, 3.45 (2.87, 4.13) for DTG/ABC/3TC, and 7.10 (5.02, 10.04) for MTRs compared to BIC/FTC/TAF.

Conclusions: : Among TE PWH who had a gap in care prior to initiating therapy or low adherence to the index therapy, individuals who indexed on BIC/FTC/TAF had lower likelihood of switch versus those starting other regimens.

Sponsorship:: Gilead Sciences, Inc.