Changes in medication utilization and adherence associated with homeless adults' entry into permanent supportive housing

BACKGROUND: Permanent supportive housing (PSH) programs, which have grown over the last decade, have been associated with changes in health care utilization and spending. However, little is known about the impact of such programs on use of prescription drugs critical for managing chronic diseases prevalent among those with unstable housing.

OBJECTIVE: To evaluate the effects of PSH on medication utilization and adherence among Medicaid enrollees in Pennsylvania. DESIGN: Difference-in-differences study comparing medication utilization and adherence between PSH participants and a matched comparison cohort from 7 to 18 months before PSH entry to 12 months post PSH entry. SUBJECTS: Pennsylvania Medicaid enrollees (n = 1375) who entered PSH during 2011-2016, and a propensity-matched comparison cohort of 5405 enrollees experiencing housing instability who did not receive PSH but received other housing services indicative of episodic or chronic homelessness (e.g., emergency shelter stays).

MAIN MEASURES: Proportion with prescription fill, mean proportion of days covered (PDC), and percent adherent (PDC ≥ 80%) for antidepressants, antipsychotics, anti-asthmatics, and diabetes medications.

KEY RESULTS: The PSH cohort saw a 4.77% (95% CI 2.87% to 6.67%) relative increase in the proportion filling any prescription, compared to the comparison cohort. Percent adherent among antidepressant users in the PSH cohort rose 7.41% (95% CI 0.26% to 14.57%) compared to the comparison cohort. While utilization increased in the other medication classes among the PSH cohort, differences from the comparison cohort were not statistically significant.

CONCLUSIONS: PSH participation is associated with increases in filling prescription medications overall and improved adherence to antidepressant medications. These results can inform state and federal policy to increase PSH placement among Medicaid enrollees experiencing homelessness.