Comparison of treatment adherence among new-start patients on lurasidone vs. other atypical antipsychotics: Results from a multi-state Medicaid population among adults with schizophrenia

Objective: 
Adherence to antipsychotic treatment among schizophrenia patients is a predictor of relapse, hospitalizations, and consequently higher costs. This study compares treatment adherence with lurasidone vs. other atypical antipsychotics during the first 6 months on therapy in Medicaid-insured adults with schizophrenia.
Methods:
Retrospective study of health insurance claims from multi-state Medicaid databases for schizophrenia patients, aged 18–64, initiating monotherapy with lurasidone, aripiprazole, olanzapine, quetiapine XR, quetiapine IR or risperidone between 10/1/2010-9/30/2011. Adherence over 6-months post-initiation evaluated using three measures: length of continuous (no therapy gaps ≥ 45 days) therapy, medication possession ratio (MPR), and discontinuation (therapy gap of ≥ 45 days) rate using pair-wise comparisons (chi-square and paired t-tests).
Results:
Qualifying patients were allocated to the following cohorts: lurasidone (n=146), aripiprazole (n=123), olanzapine (n=159), quetiapine XR (n=278), quetiapine IR (n=228) and risperidone (n=568). Mean length of continuous therapy (days) was significantly longer for lurasidone patients (mean[SD]) (107.1 [63.8]) compared to aripiprazole (84.8 [55.9]), olanzapine (87.2 [61.5]), quetiapine XR (82.2 [59.6]), quetiapine IR (82.6 [59.1]) and risperidone (79.4 [59.1]) (p<0.001). Mean MPR (mean[SD]) for lurasidone (0.60 [0.35]) was significantly higher compared to aripiprazole (0.47 [0.31]), olanzapine (0.48 [0.34]), quetiapine XR (0.46 [0.33]), quetiapine IR (0.46 [0.33]), and risperidone (0.44 [0.33]) (p<0.05). Lurasidone patients had lower treatment discontinuation rates (49%) compared to aripiprazole (64%), olanzapine (62%), quetiapine XR (63%), quetiapine IR (63%), and risperidone (66%) (p<0.05).
Conclusions:
This analysis of adult Medicaid-insured patients with schizophrenia demonstrated better adherence for lurasidone compared to aripiprazole, olanzapine, quetiapine XR, quetiapine IR, and risperidone.