Session number: 1123
Abstract title: Pharmacy Data Identifies Poorly Adherent Patients with Schizophrenia At Increased Risk for Admission
Author(s):
M Valenstein - Ann Arbor COE/SMITREC/ University of Michigan Dept of Psych
LA Copeland - Ann Arbor COE
FC Blow - SMITREC/ University of Michigan Dept of Psych
JF McCarthy - SMITREC/ University of Michigan School of Public Health
JE Zeber - SMITREC/ University of Michigan School of Public Health
L Gillon - SMITREC
CR Bingham - SMITREC/ University of Michigan Dept of Psych
T Stavenger - Dept of Veterans Affairs Ann Arbor Health System
Objectives: Anti-psychotic medications ameliorate the symptoms of schizophrenia and are an essential component of treatment. Unfortunately, many patients are poorly adherent, placing them at increased risk for relapse.
Healthcare organizations that have comprehensive pharmacy data may be in a position to systematically identify poorly adherent patients with schizophrenia. In this study, we examine whether a pharmacy-based measure of outpatient adherence, the medication possession ratio (MPR), is associated with adverse outcomes among patients with schizophrenia.
Methods: Using data from the VA National Psychosis Registry, we identified 67,079 veterans with a diagnosis of schizophrenia who filled outpatient prescriptions for one or two different antipsychotic medications between October 1, 1998 and September 30, 1999. We calculated each patient’s MPR by dividing the number of days’ supply of outpatient antipsychotic medication the veteran received by the number of days’ supply they needed to receive to take their antipsychotic continuously while in the community. Using multivariate regression and adjusting for race, age-group, and type of antipsychotic, we examined the relationship between MPRs and psychiatric admission.
Results: Patients with antipsychotic MPRs close to 1.0 during outpatient periods had the lowest rates of psychiatric admission. As patients secured progressive smaller proportions of required antipsychotic medication (and had smaller MPRs), their rates of admission gradually climbed. Forty percent of patients had MPRs less than 0.8, indicating poor adherence. Patients with poor adherence (MPRs less than 0.8) were 2.4 times as likely to be admitted as patients with good adherence (MPRs from 0.8-1.1). 23% of poorly adherent patients but only 10% of patients with good adherence were admitted. Once admitted, poorly adherent patients had more hospital days.
Conclusions: A pharmacy-based measure of antipsychotic adherence, the medication possession ratio, is strongly associated with the risk of psychiatric admission among patients with schizophrenia.
Impact statement: Many healthcare systems, including the VA, now have the capacity to use their pharmacy data to identify poorly adherent patients with schizophrenia. We urge these organizations to consider doing so. If organizations identify these at-risk patients in a timely manner and offer interventions to improve adherence, the outcomes of many patients might be improved.