Impact of switching to long-acting injectable antipsychotics on health services use in the treatment of schizophrenia.

Objective: To better understand the treatment patterns, persistence and compliance, resource use, and associated costs, of long-acting injectable antipsychotics (LAI-AP), using the Régie de l'assurance maladie du Québec database.

Method: Patients with schizophrenia or schizoaffective disorder who were incident users of an LAI-AP prescribed between January 1, 2008, and March 31, 2012, were selected. Concomitant use of oral APs and treatment persistence and compliance with LAI-AP were analyzed. Patients were considered compliant if they had a medication possession ratio (MPR) of at least 0.80. Health care resource use (HCRU) and associated costs were analyzed during the year before and after LAI-AP initiation.

Results: A total of 1992 patients met the inclusion criteria. The average persistence with LAI-AP was 217.2 days (SD 144.2). The mean MPR with LAI-AP during the postinitiation year was 0.58 (SD 0.35), with 37.5% of patients being compliant. In the preinitiation year, 29.0% of patients were compliant with previous oral AP. In the pre- and postinitiation periods, 1484 and 958 patients had at least 1 hospitalization, and hospitalized days were reduced by one-half (P<0.001). Cost of HCRU, including medication, was significantly decreased from $24,382 (SD $27,234) to $13,090 (SD $16,987), respectively, in the pre- and postinitiation years (P<0.001).

Conclusions: The initiation of an LAI-AP improved treatment compliance, compared with previous oral APs, resulted in significantly lower HCRU and costs. The primary drivers were the reduction in the occurrence and days of hospitalizations.