Objective: To compare treatment patterns and Medicaid spending between schizophrenia patients initiating once-monthly paliperidone palmitate (PP1M) and oral atypical antipsychotics (OAAs) within four comorbid populations: cardiovascular disease (CVD), diabetes, hypertension and obesity.
Methods: Five-state Medicaid data identified comorbid adults with schizophrenia initiating PP1M or OAAs (index) from September 2009 balanced with inverse probability of treatment weighting. Chi-squared and t-tests compared index antipsychotic (AP) exposure (no gap >90 days) duration, AP polypharmacy, and index AP adherence (proportion of days covered ≥80%) and persistence (no gap ≥60 days) at 12 months post-index. Linear models with a non-parametric bootstrap procedure compared costs.
Results: PP1M patients consistently had longer index AP exposure (e.g. CVD: 244 vs. 189 days; p < .001) and less AP polypharmacy (e.g. CVD: 21.1% vs. 28.1%; p < .001) versus OAA patients. Relative to OAA patients, adherence was more likely in PP1M patients with CVD or obesity (e.g. CVD: 28.6% vs. 22.1%; p < .001) and less likely for patients with diabetes (22.0% vs. 24.4%; p = .031). Persistence was consistently more likely for PP1M versus OAA patients (e.g. CVD: 49.9% vs. 27.4%; p < .001). Total costs were not significantly different between PP1M and OAA patients for any comorbidity. PP1M patients with diabetes, hypertension or obesity had higher pharmacy and lower medical costs (all p < .05).
Conclusions: Treatment with PP1M versus OAAs may reduce AP polypharmacy and increase AP persistence in comorbid patients with schizophrenia, without increasing total healthcare costs. Comorbidities are a highly prevalent driver of excess mortality in this vulnerable population; thus, future studies should specifically address the real-world effectiveness of therapies, including long acting injectable therapies (LAIs), for these patients.
Keywords: Once-monthly paliperidone palmitate; adherence; comorbidities; long-acting injectable therapies; schizophrenia.