Rates and predictors of antipsychotic non-adherence and hospitalization in Medicaid and commercially-insured patients with schizophrenia.

Objective: To assess rates and predictors of antipsychotic non-adherence and hospitalizations among patients with schizophrenia in separate Medicaid and commercial populations.

Methods: This retrospective analysis used the Thomson Reuters MarketScan Multi-State Medicaid and IMS LifeLink Health Plan claims databases. These analyses included patients with a diagnosis of schizophrenia (295.xx) who received a prescription for an antipsychotic between January 1, 2008, and June 30, 2009 (date of first claim in window defined as index). Patients were required to have one additional antipsychotic prescription in the 1 year following index. Rates of adherence and psychiatric and all-cause hospitalization were evaluated. Multivariate logistic regression models identified predictors of antipsychotic non-adherence and hospitalization. These analyses were not intended to compare outcomes between the Medicaid and commercial populations.

Results: Patients, 20,710 Medicaid and 7528 commercial, met all inclusion criteria. Both populations were ∼47% male, with a younger mean ± SD age among the Medicaid population (42.6 ± 14.1 vs 47.9 ± 17.1 years). Mean ± SD MPR in follow-up was 0.77 ± 0.25 in the Medicaid population (37.5% non-adherent) and 0.73 ± 0.27 in the commercial group (44.6% non-adherent). Rates of all-cause and psychiatric hospitalizations were 28.6% and 27.2%, respectively, among Medicaid and 29.2% and 26.3% among commercial patients. Newly starting antipsychotics and being non-adherent to therapy at baseline were both found to significantly increase the likelihood of non-adherence 12-fold in the Medicaid population (both p < 0.001) and 8-fold in the commercial population (both p < 0.001). Medicaid patients with a baseline psychiatric hospitalization had a 3-fold increased likelihood of hospitalization (p < 0.001) and commercial patients had a 2-fold increase (p < 0.001).

Conclusions: These two populations were not compared statistically; no conclusions as to the cause of any observed differences in outcomes can be made. Conclusions: Previous non-adherence, newly starting antipsychotic therapy, and previous hospitalization were significant predictors of non-adherence and hospitalization in Medicaid and commercial populations.