Predictors for Initiation of Atypical Long-Acting Injectable Antipsychotic Agents in a Commercial Claims Cohort of Individuals With Early-Phase Schizophrenia

ABSTRACT

Objective: Long-acting injectable antipsychotic agents (LAIs) have improved clinical effectiveness and adherence versus oral antipsychotic agents (OAs); however, a minority of individuals with schizophrenia are treated with LAIs compared with OAs. This cohort study aimed to evaluate predictors of initiation of atypical LAIs among patients with newly diagnosed schizophrenia in the United States.

Methods: Using claims data from IBM MarketScan Commercial and Medicare Supplemental databases between January 1, 2013, and March 31, 2020, adults with first diagnosis of schizophrenia, ≥ 1 OA claim following diagnosis, and continuous benefits were identified. To evaluate predictors of LAI initiation, a Cox proportional hazard regression model per independent predictors and main outcome (ie, LAI initiation) was performed.

Results: Of 3,639 patients with early-phase schizophrenia, 369 (10%) had ≥ 1 LAI claim(s) after ≥ 1 OA claim(s). Several factors present prior to LAI initiation were significantly (P < .0001) predictive of LAI initiation: greater monthly OA switches (hazard ratio [95% CI]: 11.39 [7.01–18.51]), unsuccessful OA implementation (3.09 [2.39–3.98]), greater monthly schizophrenia-related hospitalizations (20.83 [14.22–30.51]), and greater monthly schizophrenia-related emergency department visits (4.13 [2.07–8.22]).

Conclusions: In this analysis of pharmacy claims records for patients with early-phase schizophrenia, results suggest that LAIs are used less frequently in the early phase than reported in later stages. Their initiation is often reactive to relapse or disease exacerbation, rather than proactive as a relapse-prevention tool for early-phase schizophrenia. These data highlight the underuse of LAIs, particularly in the early phase when they could make the most difference.