title: Asthma-chronic obstructive pulmonary disease overlap syndrome in the urban Chinese population: prevalence and disease burden using the 2010, 2012, and 2013 China National Health and Wellness Surveys.
abstract: BACKGROUND
  Research has suggested a significant burden for patients with asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS). However, few studies have studied this population in the People's Republic of China, a region in the midst of rapid epidemiological change with respect to respiratory disease. The aim of this study was to assess the prevalence of ACOS and its association with patient outcomes in urban China.
  
  
  METHODS
  Data from the 2010, 2012, and 2013 China National Health and Wellness Survey, an Internet-based survey of adults in urban China, were used (N=59,935). Respondents were categorized into one of four groups based on self-reported physician diagnoses: ACOS, asthma only, COPD only, or control (ie, no asthma or COPD). A propensity score matching procedure was conducted to cull the control group into a subgroup (ie, matched controls) who resembled patients with ACOS, asthma only, and COPD only. These four groups (ACOS, asthma only, COPD only, matched controls) were then compared with respect to health status (Short Form-12 version 2/Short Form-36 version 2), work productivity, and health care resource use using generalized linear models.
  
  
  RESULTS
  Patients with ACOS (N=366) comprised 0.61% of the adult population, 30.73% of the asthma population, and 18.60% of the COPD population in the People's Republic of China. Patients with ACOS reported significantly worse health status (eg, health utilities =0.63, 0.66, 0.63, and 0.69 for ACOS, COPD only, asthma only, and matched controls, respectively) and significantly greater work impairment (eg, overall work impairment =43.65%, 35.19%, 48.55%, and 29.80%, respectively) and health care resource use (eg, physician visits in the past 6 months =5.13, 3.84, 4.65, and 2.39, respectively) compared with matched controls and patients with COPD only. Few significant differences were observed between patients with ACOS and asthma only.
  
  
  CONCLUSIONS
  Patients with ACOS have a greater comorbidity burden and significantly worse health outcomes compared with COPD only patients and matched controls. Better management of these patients may help to improve their outcomes.
authors.affiliation: Department of Global Medical Affairs, AstraZeneca, Gothenburg, Sweden.
authors.forename: Bo
authors.initials: B
authors.lastname: Ding
authors.affiliation: Department of Health Outcomes Practice, Kantar Health, New York, NY, USA.
authors.forename: Marco
authors.initials: M
authors.lastname: DiBonaventura
authors.affiliation: Department of Global Medical Affairs, AstraZeneca, Gothenburg, Sweden.
authors.forename: Niklas
authors.initials: N
authors.lastname: Karlsson
authors.affiliation: Department of Medical Affairs China, AstraZeneca, Shanghai, People's Republic of China.
authors.forename: Xia
authors.initials: X
authors.lastname: Ling
mesh_terms: D000041:Absenteeism; D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002681:China / Q000453:epidemiology; D015897:Comorbidity; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D004526:Efficiency; D004651:Employment; D005260:Female; D006295:Health Resources / Q000706:statistics & numerical data; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D057216:Propensity Score; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D011788:Quality of Life; D012307:Risk Factors; D018582:Sick Leave; D013577:Syndrome; D013997:Time Factors; D014504:Urban Health; D055815:Young Adult
keywords: ACOS; healthcare resource use; quality of life; work productivity