• Pharmacological Treatment for Serious Mental Illness: Geographic Variation and Association with Preventable Hospitalizations

      HUANG, TING-YING; Simoni-Wastila, Linda (2016)
      Background: The number of older adults with serious mental illness (SMI), including bipolar disorder, schizophrenia, and depressive disorders, is expected to increase. Yet, SMI treatment access and its association with adverse outcomes in this specific population are not well established. This study aims to quantify SMI pharmacological treatment initiation among older adults with SMI, analyze its geographic variation, and examine its association with preventable hospitalizations. Methods: Using 2006-2012 Medicare administrative and claims data, this retrospective cohort study identified fee-for-service beneficiaries newly-diagnosed with SMI. Pharmacological treatment initiation was defined as any prescription fill for medications indicated for the newly-diagnosed SMI in the 12 months after diagnosis, with no use in the 6 months before initiation. The crude and adjusted regional pharmacological treatment incidences were summarized at the hospital referral region level and examined with spatial clustering using local indicators of spatial autocorrelation (LISA). Preventable hospitalizations were measured by the count of hospital or emergency department admissions related to ambulatory care-sensitive conditions (e.g., diabetes, cardiovascular, respiratory disease) during the same follow-up period and compared between SMI treatment pharmacological initiators and nonusers. Generalized linear mixed models with random intercepts were conducted to generate all estimates, adjusting for beneficiary demographics, comorbidities, health services utilization, regional physician supply, and spatial clustering of regional SMI pharmacological treatment incidences. Results: Of the 38,607 beneficiaries aged 65 and older identified with newly-diagnosed SMI in 2008-2012, 64.8% initiated pharmacological treatment after diagnosis. The sample was predominantly female (74.0%) and white (85.1%), with a mean age of 78.5 years. LISA results visualized highly-localized regional pharmacological treatment incidences, with hot spots clustering in the Midwest and upper Pacific West and cold spots in the West South Central and lower New England regions after adjustment. Compared with nonusers, SMI pharmacological treatment initiators showed a 12% reduced risk for preventable hospitalizations (RtR 0.88, 95% CI 0.84-0.93). Conclusions: Findings suggest the majority of older adults with SMI receive pharmacological treatment after diagnosis. Clustering of regional SMI pharmacological treatment incidences implies locally-shared physician practice styles in treating SMI. Timely SMI pharmacological treatment initiation plays an important role in managing risks for preventable adverse outcomes.
    • Use of Antipsychotics in Medicare Part D: The Role of Coverage Restrictions and Impact of Medication Adherence on Hospitalization and Spending For Beneficiaries with Serious Mental Illness

      Roberto, Pamela; Stuart, Bruce C. (2016)
      Background: Coverage restrictions for antipsychotics are associated with access problems in Medicaid but their impact in Medicare Part D is unknown. The relationship between antipsychotic adherence, hospitalization risk, and treatment costs among Part D enrollees with serious mental illness also has not been systematically examined. Evaluating the association between adherence and outcomes is complicated by a recent policy change requiring the redaction of substance abuse claims from the Medicare research files, as hospitalizations and spending for beneficiaries with serious mental illness-many of whom have comorbid substance abuse disorders-may be systematically underreported. Methods: Enrollment, formulary, utilization, and spending data were obtained from the CMS Chronic Conditions Warehouse for 2011-2012. Effects of coverage restrictions on antipsychotic utilization were assessed by exploiting a unique natural experiment in which low-income beneficiaries were randomly assigned to prescription drug plans with varying levels of formulary generosity. The scope of the substance abuse claims redaction was determined by comparing unredacted beneficiary-level expenditure data to expenditures calculated from the redacted claims. Antipsychotic adherence was measured by the proportion of days covered (PDC) and stratified into four categories: PDC<0.70; 0.70≤PDC<0.80; 0.80≤PDC<0.90; and PDC≥0.90. Probit regressions and two-part generalized linear models were used to examine relationships between adherence in year one and hospitalizations and expenditures, respectively, in year two. Results: Despite considerable variation in the use of coverage restrictions across Part D plans, there was no evidence that restrictions significantly altered utilization patterns or reduced overall utilization of antipsychotics. Nearly one in five Part D enrollees with serious mental illness had claims affected by the redaction and average Part A spending among those with redacted claims was underreported by 57%. Based on analysis of the unredacted data, adherence to antipsychotic therapy was associated with significantly lower probability of psychiatric hospitalization and lower hospital expenditures. Conclusions: Coverage restrictions do not limit access to antipsychotics among Part D enrollees. Benefits of sustained adherence to antipsychotics for beneficiaries with serious mental illness include lower probability of psychiatric hospitalization and lower hospital spending. Researchers should exercise caution when using redacted Medicare claims to analyze utilization and spending outcomes for this population.