Treatment patterns in Medicaid patients with schizophrenia initiated on a first- or second-generation long-acting injectable versus oral antipsychotic

Dominic Pilon, Kruti Joshi, Neeta Tandon, Marie-Hélène Lafeuille, Rhiannon L Kamstra, Bruno Emond, Patrick Lefebvre

Poor antipsychotic (AP) adherence is a key issue in patients with schizophrenia. First-generation antipsychotic (FGA) and second-generation antipsychotic (SGA) long-acting injectable therapies (LAI) may improve adherence compared to oral antipsychotics (OAP). The objective of the study was to compare treatment adherence and persistence in Medicaid patients with schizophrenia initiated on first-generation long-acting injectable therapies (FGA-LAI) or second-generation long-acting injectable therapies (SGA-LAI) versus OAP. Adults with schizophrenia initiated on FGA-LAI, SGA-LAI, or OAP on or after January 2010 were identified using a six-state Medicaid database (January 2009-March 2015). Outcomes were assessed during the 12 months following treatment initiation. Index medication adherence was assessed using the proportion of days covered ≥80%, while persistence was assessed as no gap of ≥30, ≥60, or ≥90 days between days of supply. Outcomes were compared between FGA/SGA-LAI and OAP cohorts using chi-squared tests and adjusted odds ratios (OR). During follow-up, AP polypharmacy was more common in FGA-LAI patients (N=1,089; 36%; P=0.029) and less common in SGA-LAI patients (N=2,209; 27%; P<0.001) versus OAP patients (N=20,478; 33%). After adjustment, SGA-LAI patients had 24% higher odds of adherence at 12 months (OR: 1.24; P<0.001), in contrast to FGA-LAI patients who had 48% lower odds of adherence (OR: 0.52; P<0.001) relative to OAP patients. SGA-LAI patients were more likely to be persistent (no gap ≥60 days) at 12 months than OAP patients (37% vs 30%; P<0.001), but not FGA-LAI patients (31% vs 30%; P=0.776). In comparison to OAP patients, SGA-LAI patients had 46% higher adjusted odds of persistence (no gap ≥60 days; OR: 1.46; P<0.001), while FGA-LAI patients were not significantly different (OR: 0.95; P=0.501). Medicaid patients initiated on SGA-LAI demonstrated better treatment adherence and persistence compared to OAP patients, while those initiated on FGA-LAI did not show significant improvement in adherence or persistence and had more AP polypharmacy relative to OAP patients. These findings suggest the potential value of SGA-LAI in the treatment of schizophrenia.