title: Impact of maintenance therapy on hospitalization and expenditures for Medicare beneficiaries with chronic obstructive pulmonary disease.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) is associated with high levels of hospitalization and health care expenditures among the aged. Adherence to appropriate maintenance drug regimens has been reported to reduce hospitalization and health care spending in clinical trials. However, little research has been conducted to compare use versus nonuse of these medications in terms of health-related outcomes in routine practice.
  
  
  OBJECTIVE
  The purpose of this study was to compare differences between users and nonusers of maintenance medications in terms of selected outcomes for a nationally representative sample of Medicare beneficiaries with COPD.
  
  
  METHODS
  The study sample was selected from Medicare Current Beneficiary Surveys conducted between 1997 and 2005. Beneficiaries with COPD who used ≥1 maintenance medication annually were compared with nonusers on 3 claims-based outcomes: any hospitalization, any rehospitalization within 31 days, and total annual Medicare expenditures.
  
  
  RESULTS
  The study sample consisted of 6322 Medicare beneficiaries who contributed a total of 9161 person-year observations for analysis. Over the 9-year study period, 39.9% (3659/9161) of the person-year observations were recorded for maintenance medication users, and 60.1% (5502/9161) were recorded for nonusers. Most of the observations for medication users involved beneficiaries who were female (50.1% [1833/3659]), non-Hispanic white (85.4% [3124/3659]), and ≥65 years of age (88.2% [3228/3659]); most of the observations for nonusers involved beneficiaries who were male (51.9% [2855/5502]), non-Hispanic white (82.7% [4550/5502]), and ≥65 years of age (88.1% [4848/5502]). Annually, 40% of the sample filled prescriptions for COPD maintenance medications. In multivariate models, maintenance drug users were less likely than nonusers to be hospitalized (odds ratio [OR] = 0.70; 95% CI, 0.61 to 0.79) or rehospitalized (OR= 0.74; 95% CI, 0.63 to 0.87), and had significantly lower annual Medicare expenditures (-$3916; 95% CI, -$4977 to -$2854).
  
  
  CONCLUSIONS
  In this comparison of users and nonusers of maintenance medication for COPD, use of maintenance therapy was associated with significantly lower risks of hospitalization and rehospitalization and reduced Medicare expenditures.
authors.affiliation: Peter Lamy Center on Drug Therapy and Aging, University of Maryland School of Pharmacy, Baltimore, MD, USA.
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Stuart
authors.forename: Linda
authors.initials: L
authors.lastname: Simoni-Wastila
authors.forename: Ilene H
authors.initials: IH
authors.lastname: Zuckerman
authors.forename: Amy
authors.initials: A
authors.lastname: Davidoff
authors.forename: Thomas
authors.initials: T
authors.lastname: Shaffer
authors.forename: Hui-wen Keri
authors.initials: HW
authors.lastname: Yang
authors.forename: Jingjing
authors.initials: J
authors.lastname: Qian
authors.forename: Anand A
authors.initials: AA
authors.lastname: Dalal
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Mapel
authors.forename: Lynda
authors.initials: L
authors.lastname: Bryant-Comstock
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D015897:Comorbidity; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data* / Q000639:trends; D019538:Health Care Surveys; D006760:Hospitalization; D006801:Humans; D008297:Male; D006278:Medicare; D055118:Medication Adherence; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D017410:Practice Guidelines as Topic; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000191:economics* / Q000628:therapy; D012307:Risk Factors; D014481:United States