Factors Associated with the Initiation of Long-Acting Injectable Paliperidone Palmitate Versus Aripiprazole Among Medicaid Patients with Schizophrenia: An Observational Study.

Introduction: Factors underlying the selection of antipsychotics for patients with schizophrenia are poorly understood. This study investigated variables associated with initiation of treatment with the long-acting injectables paliperidone palmitate (LAI-PP) and aripiprazole LAI (LAI-AP) in Medicaid patients with schizophrenia.

Methods: Adults with at least one medical or pharmacy claim for LAI-PP or LAI-AP from 1 January 2013 to 31 December 2016 were selected from the IBM MarketScan Medicaid Database. The date of the first LAI-PP or LAI-AP claim was the index date. Patients who had at least two medical claims, on different days, for a schizophrenia diagnosis and at least 12 months of continuous health plan enrollment prior to index date were included in the analysis. Multivariable logistic regression was performed to determine the factors associated with the initiation of LAI-PP versus LAI-AP.

Results: Of included patients, 5501 initiated LAI-PP and 1449 initiated LAI-AP. Patients more likely to initiate LAI-PP versus LAI-AP were older, male, or African American (all p < 0.01). Patients with obesity (odds ratio [OR] 0.84; 95% confidence interval [CI] 0.71, 0.98), post-traumatic stress disorder (OR 0.76; 95% CI 0.63, 0.92), or prior oral antipsychotic use (OR 0.66; 95% CI 0.55, 0.79) were less likely to initiate LAI-PP; whereas, patients with nonorganic psychoses (OR 1.35; 95% CI 1.18, 1.55) or prior use of other injectable antipsychotics (OR 1.26; 95% CI 1.09, 1.47) were more likely to initiate LAI-PP versus LAI-AP. Patients with at least two all-cause hospitalizations were 1.37 times more likely to initiate LAI-PP vs LAI-AP (OR 1.37; 95% CI 1.18, 1.60).

Conclusion: Factors associated with initiating LAI-PP and LAI-AP differed. Notably, patients who initiated LAI-PP had greater prior use of medical services than LAI-AP patients. Understanding prescribing practices may help optimize treatment strategies and improve disease management.

Funding: Janssen Scientific Affairs, LLC.