• Antiparkinson Drug Use and Adherence, and the Impact on Medicare Part D Enrollees with Parkinson's disease

      Wei, Yu Jung; Palumbo, Francis Bernard, 1945- (2012)
      Study Objectives: To examine the prevalence of and factors associated with Antiparkinson drug (APD) use and adherence, and the association of APD use and adherence with healthcare utilization and expenditures in Medicare Part D enrollees with Parkinson's disease (PD). Methods: A retrospective observational study was conducted using the 2006-2007 Medicare Chronic Care Condition Warehouse data which represents a 5 percent sample of Medicare beneficiaries. The PD sample was selected with (1) at least 1 medical claim with an ICD-9 code 332.0 in two consecutive years; and (2) continuous enrollment in Medicare Parts A, B, and D from 6/1/2006 through 12/31/2007 or date of death. The total study interval was 579 days. APD use measures included any use, duration, and adherence (Medication Possession Ratio [MPR]). Factors associated with APD use measures were examined using modified-Poisson regressions with Generalized Estimating Equations. The association of APD use/adherence with utilization and expenditure outcomes was evaluated with negative binomial and gamma General Linear Models, respectively. Results: 12% of PD patients (n=8,758) did not use any APDs, and a fourth of APD users had a duration of therapy for 435 days or fewer and an MPR of less than 0.80. Patients with cognitive impairment and with 11 or more comorbidities were less likely to use APDs; and if using, they were less likely to possess APDs persistently and regularly. Other factors associated with not using APDs included low-income-subsidy eligibility and having no neurologist visits. Factors associated with poor adherence included older age (65 or older), non-white ethnicity, and having changes in APD therapy. Longer duration and higher adherence were associated with a reduced rate of all-cause utilization for acute (hospital and emergency room [ER]), chronic (Part A skilled nursing facility [SNF] and home health agency), and physician care (only for adherence). Similar patterns were found with PD-only and PD-related-comorbidities hospital, ER, and Part A SNF care. Also, significantly reduced total, Part A, and Part B, and increased Part D expenditures were observed in longer-duration users and in higher adherers. Conclusion: Significant reduction in healthcare utilization and expenditures could be achieved by improved duration of use and adherence to APDs.
    • Mapping Expanded Prostate Cancer Index Composite (EPIC) Questionnaire to EuroQoL-5D (EQ-5D) Utility Weights to Inform Economic Evaluations for Prostate Cancer

      Khairnar, Rahul; Palumbo, Francis Bernard, 1945- (2020)
      OBJECTIVES: To develop a mapping algorithm to obtain EuroQoL-5D-3L (EQ5D) health utilities from Expanded Prostate Cancer Index Composite (EPIC) questionnaire. METHODS: This mapping study utilized baseline data from an international, multicenter, randomized controlled trial (NCT00331773) of patients with low-risk prostate cancer. Patient health-related quality-of-life (HRQoL) data were collected using EPIC and health utilities were obtained using EQ5D. Data were divided into an estimation sample (n=765, 70%) and a validation sample (n=327, 30%). The relationship between the instruments was estimated using ordinary least squares (OLS), Tobit, and two-part models. Five-fold cross-validation (in-sample) was used to compare the predictive performance of the estimated models. Final models were selected based on root mean square error (RMSE). OLS models using baseline cross-sectional data, combined data from all assessment periods, and random effects (RE) models that explicitly model the longitudinal nature of the data were estimated to compare predictive ability of algorithms derived from cross-sectional and longitudinal data. Longitudinal predictive performance of OLS models derived using baseline data was examined in the post-intervention data. RESULTS: A total of 565 patients in the estimation sample had complete information on both EPIC and EQ5D questionnaires at baseline. Mean observed EQ5D utility was 0.90±0.13 (range: 0.28-1) with 55% of patients in full health. Low to moderate correlations were found between EQ5D utility and urinary (r=0.38), bowel (r=0.34) and hormonal (r=0.55) domains of EPIC; sexual domain was weakly correlated (r=0.18) with EQ5D utility. OLS models outperformed their counterpart models for all pre-determined model specifications. The best model fit was: “EQ5D utility = 0.248541 + 0.000748*(Urinary Function) + 0.001134*(Urinary Bother) + 0.000968*(Hormonal Function) + 0.004404*(Hormonal Bother) – 0.376487*(Zubrod) + 0.003562*(Urinary Function*Zubrod)”; RMSE was 0.10462. When comparing cross-sectional vs. longitudinal data, a mapping algorithm obtained using combined EPIC subdomain data outperformed other model types. Mean absolute differences (MDs) between reported and predicted were low in general and decreased as the time of assessment increased. CONCLUSIONS: This study identified mapping algorithms to generate EQ5D utilities from EPIC domain or sub-domain scores, with satisfactory longitudinal predictive performance. The study results will help estimate quality-adjusted life-years in future economic evaluations of prostate cancer treatments.
    • Use of pharmacoeconomic data for formulary decision making in teaching hospitals

      Kulsomboon, Vithaya; Palumbo, Francis Bernard, 1945- (2000)
      A national mail survey of Pharmacy Directors in teaching hospitals was performed to determine the criteria and applicability of the use of Pharmacoeconomics (PE) data for formulary decisions, to identify the determinants of PE-based formulary decisions, and to assess the quality of available PE data. Of the 166 (39.6%) hospitals responding to the survey during April through July, 1999, 83.1% reported using PE-based formulary decisions. The two significant determinants of whether hospitals used or did not use PE data were census and annual pharmacy drug budgets. The two most important criteria for PE data use were the impact of a new medication on institutional costs and the anticipated annual budget for a new medication. To determine the degree of use of PE-based formulary decisions, principal components analysis was employed to reduce and classify survey-items for a PE-index. PE-index scores were calculated by summing the PE-index item scores. A stepwise multiple regression showed that five determinants jointly explained 49.8% of the variance (Adjusted R2 = 46.7%) of the PE-index scores [F (7,115) = 16.3, p < 0.001]. Hospitals with higher cost-savings from using PE data, higher FTEs, higher number of staff types responsible for PE analyses, and ranking of anti-infective drugs as the most important drug class in requiring PE data, were associated with an increase in PE-index scores. "Hospitals located in the South" was associated with a decrease in PE-index scores. Hospitals reporting a higher degree of comfort if PE data were reviewed and approved by the FDA expected an increase in PE data use. The study findings suggest that the hospitals use PE data based on cost impact to their institutions. Cost-savings from PE-based formulary decisions would motivate hospitals to devote more resources to PE evaluations and increase the use of PE data. The use of PE data from pharmaceutical companies might increase if the FDA reviewed and approved such data.