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Trajectories of Treatment Disruption for Chronic Outpatient Medications for U.S. Veterans During Drug Shortages

Year: 2026

Type: article

Abstract: INTRODUCTION: Although drug shortages for outpatient chronic conditions commonly occur, population-level data on how they impact patients' ability to refill prescriptions is scarce. We sought to identify distinct patterns of refill adherence following drug shortages and patient- and prescription-level factors associated with adherence trajectories reflecting potential shortage-related treatment disruption. METHODS: We retrospectively analyzed panel data assembled from 2017 to 2020 Veterans Health Administration (VHA) electronic health record data. Patients were included if they were baseline users of medications subject to a shortage within VHA. Group-based trajectory modeling was applied to users' monthly proportion of days covered (PDC) values from 6-months before to 6-months after the reported drug supply chain disruption. Patient demographics and medication characteristics were compared between identified trajectory groups using multivariable logistic regression. RESULTS: Among 1.5 million episodes of medication use (representing 1.3 million unique Veterans) for 29 medications in shortage in VHA, 6.3% were for female patients and the mean age was 66.4 ± 12.8 years. A 4-group trajectory model had the best fit: High Adherence (69.2% of observations), Moderate Adherence (14.1%), Potential Shortage-Related Disruption (8.5%), and Pre-Shortage Disruption (8.3%). Drug characteristics (drug class, number of manufacturers) were more strongly associated than patient characteristics with having Potential Shortage-Related Treatment Disruption vs. High Adherence. CONCLUSIONS: We identified 4 trajectories of refill adherence for medications subject to VHA drug shortages, with 8.5% of users of affected drugs exhibiting a trajectory consistent with shortage-related treatment disruption. Drug characteristics may modify whether drug shortages lead to treatment disruption in VHA.

Source: Pharmacoepidemiology and Drug Safety

DOI: 10.1002/pds.70393