2011 HSR&D National Meeting Abstract
1080 — MHICM and Antipsychotic Medication Adherence
Valenstein M (Ann Arbor COE/SMITREC), McCarthy JF
(Ann Arbor COE/SMITREC), Ganoczy D
(Ann Arbor COE/SMITREC), Dixon LB
(VISN 5 MIRECC/University of Maryland), Miller R
(University of Michigan), Slade EP
(VISN 5 MIRECC/University of Maryland)
For many patients with serious mental illness (SMI), antipsychotic medications are an essential component of treatment. However, approximately 30-40% have poor adherence in any given year. The VA Mental Health Intensive Case Management (MHICM) program provides a complex bundle of services to a highly disabled population of Veterans with SMI and may reduce inpatient days. We assess the impact of MHICM enrollment on antipsychotic medication adherence, as this may be an important mechanism by which MHICM programs influence treatment outcomes.
Using data from the VA National Psychosis Registry and other sources, we identified a national sample of veterans who were eligible for VA MHICM services in fiscal years 2001 to 2004 by virtue of a recorded diagnosis of schizophrenia or bipolar disorder, residence within 60 miles of a VA MHICM program, and high hospital use. We identified 946 new MHICM clients who had sufficient outpatient observation days to calculate an antipsychotic medication possession ratio (MPR) for each of five sequential 6-month periods, starting with the 6 months prior to enrollment. We matched MHICM patients 1:1 with controls based on treatment propensity scores. We used General Estimating Equations (GEE) to assess differences in medication adherence over time.
In the six months prior to enrollment or the index date, 71% of MHICM enrollees and 69% of matched non enrollees had MPRs > 0.8, indicating high levels of adherence. In each of the subsequent 6 periods the percent of patients with MPRs > 0.8 were higher in the MHICM group. In these 6-month periods, the percentage of MHICM enrollees with MPRs > 0.8 ranged from 72-80% and the percentage of control patients with MPRs > 0.8 ranged from 55-59% . In GEE analyses examining adherence over time, MHICM enrollment had an OR of 2.5 (95% CI 2.15, 2.96) for good adherence.
MHICM enrollment is associated with substantially better levels of antipsychotic adherence among VA patients with SMI. This effect persists over time.
This is the largest study to assess the impact of MHICM services on medication adherence. Increased antipsychotic adherence may be an important mechanism underlying the impact of these complex bundled services.