title: Systematic Analysis of Self-Reported Comorbidities in Large Cohort Studies - A Novel Stepwise Approach by Evaluation of Medication.
abstract: OBJECTIVE
  In large cohort studies comorbidities are usually self-reported by the patients. This way to collect health information only represents conditions known, memorized and openly reported by the patients. Several studies addressed the relationship between self-reported comorbidities and medical records or pharmacy data, but none of them provided a structured, documented method of evaluation. We thus developed a detailed procedure to compare self-reported comorbidities with information on comorbidities derived from medication inspection. This was applied to the data of the German COPD cohort COSYCONET.
  
  
  METHODS
  Approach I was based solely on ICD10-Codes for the diseases and the indications of medications. To overcome the limitations due to potential non-specificity of medications, Approach II was developed using more detailed information, such as ATC-Codes specific for one disease. The relationship between reported comorbidities and medication was expressed by a four-level concordance score.
  
  
  RESULTS
  Approaches I and II demonstrated that the patterns of concordance scores markedly differed between comorbidities in the COSYCONET data. On average, Approach I resulted in more than 50% concordance of all reported diseases to at least one medication. The more specific Approach II showed larger differences in the matching with medications, due to large differences in the disease-specificity of drugs. The highest concordance was achieved for diabetes and three combined cardiovascular disorders, while it was substantial for dyslipidemia and hyperuricemia, and low for asthma.
  
  
  CONCLUSIONS
  Both approaches represent feasible strategies to confirm self-reported diagnoses via medication. Approach I covers a broad spectrum of diseases and medications but is limited regarding disease-specificity. Approach II uses the information from medications specific for a single disease and therefore can reach higher concordance scores. The strategies described in a detailed and reproducible manner are generally applicable in large studies and might be useful to extract as much information as possible from the available data.
authors: Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, University Hospital LMU Munich, München, Germany.|Comprehensive Pneumology Center Munich, DZL, German Center for Lung Research, München, Germany.
authors: Tanja
authors: T
authors: Lucke
authors: Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, University Hospital LMU Munich, München, Germany.|Center for International Health, Ludwig-Maximilian University Munich, München, Germany.
authors: Ronald
authors: R
authors: Herrera
authors: German Research Center for Environmental Health, Institute of Health Economics and Health Care Management, Member of the German Center for Lung Research, Comprehensive Pneumology Center Munich (CPC-M), Neuherberg, Germany.
authors: Margarethe
authors: M
authors: Wacker
authors: German Research Center for Environmental Health, Institute of Health Economics and Health Care Management, Member of the German Center for Lung Research, Comprehensive Pneumology Center Munich (CPC-M), Neuherberg, Germany.
authors: Rolf
authors: R
authors: Holle
authors: Institute for Biostatistics, Hannover Medical School, Hannover, Germany.
authors: Frank
authors: F
authors: Biertz
authors: Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, University Hospital LMU Munich, München, Germany.|Comprehensive Pneumology Center Munich, DZL, German Center for Lung Research, München, Germany.
authors: Dennis
authors: D
authors: Nowak
authors: Comprehensive Pneumology Center Munich, DZL, German Center for Lung Research, München, Germany.|Thoracic Oncology Center Munich (TOM), University Hospital LMU Munich, München, Germany.
authors: Rudolf M
authors: RM
authors: Huber
authors: Pulmonary and Critical Care Medicine, Department of Medicine, University Medical Centre Giessen and Marburg, Philipps-University, Marburg, Germany.
authors: Sandra
authors: S
authors: Söhler
authors: Pulmonary and Critical Care Medicine, Department of Medicine, University Medical Centre Giessen and Marburg, Philipps-University, Marburg, Germany.
authors: Claus
authors: C
authors: Vogelmeier
authors: Department of Respiratory Medicine, Allergology and Sleep Medicine, Klinikum Nuremberg, Nürnberg, Germany.|Paracelsus Medical University Nuremberg, Nürnberg, Germany.
authors: Joachim H
authors: JH
authors: Ficker
authors: Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilian University Munich, München, Germany.
authors: Harald
authors: H
authors: Mückter
authors: Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, University Hospital LMU Munich, München, Germany.|Comprehensive Pneumology Center Munich, DZL, German Center for Lung Research, München, Germany.
authors: Rudolf A
authors: RA
authors: Jörres
mesh_terms: D000368:Aged; D015331:Cohort Studies; D015897:Comorbidity; D003625:Data Collection; D004358:Drug Therapy / Q000706:statistics & numerical data; D006801:Humans; D038801:International Classification of Diseases; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy / Q000453:epidemiology; D057566:Self Report