title: Validity of COPD diagnoses reported through nationwide health insurance systems in the People's Republic of China.
abstract: BACKGROUND
  COPD is the fourth leading cause of death worldwide, with particularly high rates in the People's Republic of China, even among never smokers. Large population-based cohort studies should allow for reliable assessment of the determinants of diseases, which is dependent on the quality of disease diagnoses. We assessed the validity of COPD diagnoses collected through electronic health records in the People's Republic of China.
  
  
  METHODS
  The CKB study recruited 0.5 million adults aged 30-79 years from ten diverse regions in the People's Republic of China during the period 2004-2008. During 7 years of follow-up, 11,800 COPD cases were identified by linkage with mortality registries and the national health insurance system. We randomly selected ~10% of the reported COPD cases and then undertook an independent adjudication of retrieved hospital medical records in 1,069 cases.
  
  
  RESULTS
  Overall, these 1,069 cases were accrued over a 9-year period (2004-2013) involving 153 hospitals across ten regions. A diagnosis of COPD was confirmed in 911 (85%) cases, corresponding to a positive predictive value of 85% (95% confidence interval [CI]: 83%-87%), even though spirometry testing was not widely used (14%) in routine hospital care. The positive predictive value for COPD did not vary significantly by hospital ranking or calendar period, but was higher in men than women (89% vs 79%), at age ≥70 years than in younger people (88%, 95% CI: 85%-91%), and when the cases were reported from both death registry and health insurance systems (97%, 95% CI: 94%-100%). Among the remaining cases, 87 (8.1%) had other respiratory diseases (chiefly pneumonia and asthma; n=85) and 71 (6.6%) cases showed no evidence of any respiratory disease on their clinical records.
  
  
  CONCLUSIONS
  In the People's Republic of China, COPD diagnoses obtained from electronic health records are of good quality and suitable for large population-based studies and do not warrant systematic adjudication of all the reported cases.
authors.affiliation: Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, UK.
authors.forename: Om P
authors.initials: OP
authors.lastname: Kurmi
authors.affiliation: Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, UK.
authors.forename: Julien
authors.initials: J
authors.lastname: Vaucher
authors.affiliation: Tobacco Medicine and Tobacco Cessation Center, China-Japan Friendship Hospital, Beijing, People's Republic of China.
authors.forename: Dan
authors.initials: D
authors.lastname: Xiao
authors.affiliation: Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, UK.
authors.forename: Michael V
authors.initials: MV
authors.lastname: Holmes
authors.affiliation: National Coordinating Centre for China Kadoorie Biobank Study, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Worldwide Epidemiology, GlaxoSmithKline R&D, Collegeville, PA, USA.
authors.forename: Kourtney J
authors.initials: KJ
authors.lastname: Davis
authors.affiliation: National Clinical Research Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing, People's Republic of China.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Medical Research Center, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, People's Republic of China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Qin
authors.affiliation: Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, UK.
authors.forename: Iain
authors.initials: I
authors.lastname: Turnbull
authors.affiliation: Radiology Department, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Peng
authors.affiliation: National Coordinating Centre for China Kadoorie Biobank Study, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Bian
authors.affiliation: Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Clarke
authors.affiliation: Department of Epidemiology, School of Public Health, Peking University Health Science Center, Beijing, People's Republic of China.
authors.forename: Liming
authors.initials: L
authors.lastname: Li
authors.affiliation: Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, UK.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, UK.
authors.forename: Zhengming
authors.initials: Z
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D002681:China; D005260:Female; D006801:Humans; D007348:Insurance, Health; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis*; D015203:Reproducibility of Results
keywords: COPD; COPD exacerbations; events adjudication; spirometry