Antipsychotic adherence and emergency department utilization among patients with schizophrenia.

This retrospective cohort study evaluated the relationship between antipsychotic medication adherence and emergency department (ED) utilization for 7851 Medicaid patients with schizophrenia enrolled in Community Care of North Carolina (CCNC). Claims and pharmacy data from January to December 2015 were collected. Medication adherence was approximated using the medication possession ratio (MPR). Negative binomial regressions estimated the effect of antipsychotic adherence on rates of medical and psychiatric ED visits. The results demonstrated a statistically significant negative relationship between antipsychotic adherence and medical ED utilization. Non- and partially adherent patients (MPR < 0.80) had 1.61 times the rate of medical ED visits as fully adherent patients (MPR ≥ 0.80) (95% CI: 1.50-1.74, p-value < 0.001). The relationship between adherence and psychiatric utilization was small and not statistically significant. The most common diagnostic categories of ED visits were injuries and poisonings (16%), ill-defined symptoms (14%), and musculoskeletal conditions (12%). This study demonstrates a clear association between antipsychotic adherence and medical ED utilization, suggesting an important link between psychiatric management and medical utilization in patients with schizophrenia.