Comparison of readmission data between different categories of antipsychotic drugs at a state psychiatric hospital in Oregon

This chart review utilizes readmission rates and mean time to readmission as markers of drug efficacy to compare different categories of long-acting injectable antipsychotics (LAIAs), antipsychotic polypharmacy, and clozapine to oral antipsychotic monotherapy (OM) at a state psychiatric hospital in Oregon (Oregon State Hospital). Methods: Charts were reviewed for patients discharged between October 20, 2011, and September 23, 2015, with a diagnosis of schizophrenia spectrum or mood disorder. Admission dates, discharge dates, and discharge antipsychotics were reviewed for each patient dating back to 1991. Discharge antipsychotics were categorized into groupings of LAIAs, antipsychotic polypharmacy, and clozapine and compared with OM to assess readmission data within 1, 3, and 5 years of discharge. The primary end point was readmission rate, measured as a percentage, and the secondary end point was mean time to readmission (MTR), measured in days. Results: Of 1088 patients reviewed, there were 2031 patient discharges associated with antipsychotic agents and 1258 readmissions. Patients discharged on LAIA monotherapy or clozapine generally had a lower readmission rate, and patients discharged on antipsychotic polypharmacy generally had a higher readmission rate. Statistical significance for these findings varied over time frames and subgroup analyses. The most notable finding for the secondary end point was a significantly shorter MTR for patients discharged on clozapine for all diagnoses and the subgroup analysis of schizoaffective disorder. Discussion: These results are only a reflection of the patient population at this hospital, and additional reviews at other facilities with different patient characteristics could clarify applicability to other patient populations.