title: Asthma-COPD overlap syndrome in the US: a prospective population-based analysis of patient-reported outcomes and health care utilization.
abstract: BACKGROUND
  Prior work suggests that asthma-COPD overlap syndrome (ACOS) has a greater health burden than asthma alone or COPD alone. In the current study, we have further evaluated the health burden of ACOS in a nationally representative sample of the US population, focusing on patient-reported outcomes and health care utilization and on comparisons with asthma alone and COPD alone. Patient-reported outcomes are especially meaningful, as these include functional activities that are highly valued by patients and are the basis for patient-centered care.
  
  
  METHODS
  Using data from the Medical Expenditure Panel Survey (MEPS), we evaluated patient-reported outcomes and health care utilization among participants who were aged 40-85 years and had self-reported, physician-diagnosed asthma or COPD. MEPS administered five rounds of interviews, at baseline and approximately every 6 months over 2.5 years. Patient-reported outcomes included activities of daily living (ADLs), mobility, social/recreational activities, disability days in bed, and health status (Short Form 12, Version 2). Health care utilization included outpatient and emergency department (ED) visits, and hospitalization.
  
  
  RESULTS
  Of 3,486 participants with asthma or COPD, 1,585 (45.4%) had asthma alone, 1,294 (37.1%) had COPD alone, and 607 (17.4%) had ACOS. Relative to asthma alone, ACOS was significantly associated with higher odds of prevalent disability in ADLs and limitations in mobility and social/recreational activities (adjusted odds ratios [adjORs]: 1.91-3.98), as well as with higher odds of incident limitations in mobility and social/recreational activities, disability days in bed, and respiratory-based outpatient and ED visits, and hospitalization (adjORs: 1.86-2.35). In addition, ACOS had significantly worse physical and mental health scores than asthma alone (P-values <0.0001). Relative to COPD alone, ACOS was significantly associated with higher odds of prevalent limitations in mobility and social/recreational activities (adjORs: 1.68-2.06), as well as with higher odds of incident disability days in bed and respiratory-based outpatient and ED visits (adjORs: 1.48-1.74). In addition, ACOS had a significantly worse physical health score, but similar mental health score, as compared with COPD alone (P-values 0.0025 and 0.1578, respectively).
  
  
  CONCLUSIONS
  In the US, ACOS is associated with a greater health burden, including patient-reported outcomes and health care utilization, relative to asthma alone and COPD alone.
authors.affiliation: Department of Medicine, Yale School of Medicine, New Haven; Veterans Affairs Clinical Epidemiology Research Center, West Haven.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Vaz Fragoso
authors.affiliation: Department of Medicine, Yale School of Medicine, New Haven.
authors.forename: Terrence E
authors.initials: TE
authors.lastname: Murphy
authors.affiliation: Department of Medicine, Yale School of Medicine, New Haven.
authors.forename: George O
authors.initials: GO
authors.lastname: Agogo
authors.affiliation: Department of Medicine, Yale School of Medicine, New Haven; Department of Biostatistics, Yale School of Public Health, New Haven, CT, USA.
authors.forename: Heather G
authors.initials: HG
authors.lastname: Allore
authors.affiliation: Department of Medicine, Yale School of Medicine, New Haven.
authors.forename: Gail J
authors.initials: GJ
authors.lastname: McAvay
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care / Q000191:economics / Q000706:statistics & numerical data; D001249:Asthma / Q000175:diagnosis / Q000191:economics / Q000503:physiopathology / Q000628:therapy*; D001510:Bed Rest; D017281:Cost of Illness; D004185:Disability Evaluation; D004632:Emergency Medical Services / Q000191:economics / Q000706:statistics & numerical data; D005260:Female; D006295:Health Resources / Q000191:economics / Q000706:statistics & numerical data*; D006304:Health Status; D017721:Hospital Costs; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D015999:Multivariate Analysis; D016017:Odds Ratio; D010343:Patient Admission / Q000191:economics; D000071066:Patient Reported Outcome Measures; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000191:economics / Q000503:physiopathology / Q000628:therapy*; D018570:Risk Assessment; D012307:Risk Factors; D012919:Social Behavior; D016896:Treatment Outcome; D014481:United States
keywords: activities of daily living; disability; mobility; recreational; social