title: Do patients consistently report comorbid conditions over time?: results from the prostate cancer outcomes study.
abstract: BACKGROUND
  Comorbidity is an important dimension of patient health status. However, limited attention has been given to assessing the reliability of patient-reported data on comorbid conditions.
  
  
  OBJECTIVE
  We sought to evaluate the consistency of self-report of 12 comorbid conditions at 3 distinct time points and examine the sociodemographic, clinical, health status, and survey factors associated with reliability.
  
  
  METHODS
  We undertook a longitudinal cohort analysis of survey and medical record abstract data obtained from a population-based sample of 3095 prostate cancer survivors.
  
  
  METHODS
  Consistent and inconsistent response patterns were assessed using descriptive statistics and regression modeling.
  
  
  RESULTS
  More than half of the cohort demonstrated consistent responses to all comorbid condition questionnaire items. Arthritis had the highest (13%) and liver disease the lowest (1%) proportion of inconsistent responses. Older age, lower income, and poorer general and mental health status were significant predictors of inconsistent responses. Subset analyses of the 4 most prevalent comorbid conditions (ie, arthritis, diabetes, hypertension, and depression) showed that respondents who reported that they were limited by, or taking prescription medicine for, the condition were more likely to provide consistent responses than those neither limited nor taking medicine. Response consistencies of 92% or better were obtained for 11 of the 12 conditions.
  
  
  CONCLUSIONS
  Men with a relatively recent prostate cancer diagnosis are generally able to provide reliable reports of their concomitant health conditions. To increase the likelihood of obtaining reliable data, investigators should consider ascertaining condition severity and current medical management when querying subjects about comorbid conditions in surveys.
authors.affiliation: Health Services and Economics Branch, Applied Research Program, Surveillance Research Program, Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, Maryland 20892-7344, USA. ck97b@nih.gov
authors.forename: Carrie N
authors.initials: CN
authors.lastname: Klabunde
authors.forename: Bryce B
authors.initials: BB
authors.lastname: Reeve
authors.forename: Linda C
authors.initials: LC
authors.lastname: Harlan
authors.forename: William W
authors.initials: WW
authors.lastname: Davis
authors.forename: Arnold L
authors.initials: AL
authors.lastname: Potosky
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015897:Comorbidity; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000523:psychology; D012650:Self Disclosure; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D017741:Survivors; D014481:United States / Q000453:epidemiology