Continuity of Antipsychotic Medication and Effect on Early Relapse

Sheila R. Botts, PharmD; Gao Liu, PhD; Joseph Conigliaro, MD, MSPH; and Jeff Talbert, PhD
University of Kentucky, Lexington

This abstract presentation did not receive funding.

Background: Continuity of care between mental health sectors is a critical variable in achieving optimal patient outcomes. Gaps in medication coverage during maintenance treatment of schizophrenia and mood disorders increase the risk of relapse. Patients recently discharged from inpatient treatment may be more vulnerable to gaps in medication.

Objective: To examine the extent of antipsychotic continuity between inpatient and community mental health sectors and its relative impact on early relapse.

Methods: This is an observational study of Medicaid claims data from 1 January 2002 to 31 December 2006. All Kentucky Medicaid enrollees discharged from one state psychiatric inpatient facility and receiving an antipsychotic medication at the time of discharge were included. Continuity of medication was defined as prescription claim within 30 days of discharge for the same antipsychotic. Relapse outcome was measured as: (1) early relapse, a readmission within 60 days of discharge; and (2) time to relapse during the one-year post-discharge period. A logistic regression model controlling for yearly fixed effects was used to assess the effects of medication continuation and other variables on early relapse. Explanatory variables include race, gender, diagnosis, antipsychotic type and formulation, antipsychotic polypharmacy, length of index hospitalization, and medical comorbidity. Effect of medication continuity on time to relapse was calculated using independent sample T-test (á <0.05)

Results: A total of 666 discharge episodes were included in the sample. Four percent of the sample had a substance abuse disorder diagnosis and because its presence perfectly predicted early relapse, these patients were omitted from the final analysis reducing the sample to 641. The sample was predominantly Caucasion (62%), male (56%) and had a diagnosis of schizophrenia or psychotic-related disorder (69%). Almost half (48%) were receiving polypharmacy. Seventy-nine percent of patients did not receive an antipsychotic prescription within 30 days of discharge. Sixteen percent (107) of the sample was readmitted within 60 days and 34% (226) was readmitted within one year. Continuation of medication was associated with a longer time to relapse (142 versus 96 days, p=0.006). In the regression model (r2=0.039) continuity of medication was associated with a lower risk of early relapse (OR 0.44; CI 0.23-.83), while polypharmacy increased the risk (OR 4.47; 1.11-17.9).

Conclusions: Although the model does not capture all contributing factors for early relapse, continuity of medication emerges as a significant factor for readmission in this Medicaid population. The presence of polypharmacy was well above that reported in other public mental health sectors and increased the risk of relapse more than four times.

References
Marcus SC, Olfson M. Outpatient antipsychotic treatment and inpatient costs of schizophrenia. Schizophr Bull. 2008;34(1):173–180.

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