title: The Inaccuracy of Patient Recall for COPD Exacerbation Rate Estimation and Its Implications: Results from Central Adjudication.
abstract: BACKGROUND
  COPD exacerbation incidence rates are often ascertained retrospectively through patient recall and self-reports. We compared exacerbation ascertainment through patient self-reports and single-physician chart review to central adjudication by a committee and explored determinants and consequences of misclassification.
  
  
  METHODS
  Self-reported exacerbations (event-based definition) in 409 primary care patients with COPD participating in the International Collaborative Effort on Chronic Obstructive Lung Disease: Exacerbation Risk Index Cohorts (ICE COLD ERIC) cohort were ascertained every 6 months over 3 years. Exacerbations were adjudicated by single experienced physicians and an adjudication committee who had information from patient charts. We assessed the accuracy (sensitivities and specificities) of self-reports and single-physician chart review against a central adjudication committee (AC) (reference standard). We used multinomial logistic regression and bootstrap stability analyses to explore determinants of misclassifications.
  
  
  RESULTS
  The AC identified 648 exacerbations, corresponding to an incidence rate of 0.60 ± 0.83 exacerbations/patient-year and a cumulative incidence proportion of 58.9%. Patients self-reported 841 exacerbations (incidence rate, 0.75 ± 1.01; incidence proportion, 59.7%). The sensitivity and specificity of self-reports were 84% and 76%, respectively, those of single-physician chart review were between 89% and 96% and 87% and 99%, respectively. The multinomial regression model and bootstrap selection showed that having experienced more exacerbations was the only factor consistently associated with underreporting and overreporting of exacerbations (underreporters: relative risk ratio [RRR], 2.16; 95% CI, 1.76-2.65 and overreporters: RRR, 1.67; 95% CI, 1.39-2.00).
  
  
  CONCLUSIONS
  Patient 6-month recall of exacerbation events are inaccurate. This may lead to inaccurate estimates of incidence measures and underestimation of treatment effects. The use of multiple data sources combined with event adjudication could substantially reduce sample size requirements and possibly cost of studies.
  
  
  BACKGROUND
  www.ClinicalTrials.gov, NCT00706602.
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Switzerland. Electronic address: anja.frei@uzh.ch.
authors.forename: Anja
authors.initials: A
authors.lastname: Frei
authors.affiliation: Department of General Practice, Academic Medical Center, University of Amsterdam, the Netherlands.
authors.forename: Lara
authors.initials: L
authors.lastname: Siebeling
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Switzerland.
authors.forename: Callista
authors.initials: C
authors.lastname: Wolters
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Switzerland.
authors.forename: Leonhard
authors.initials: L
authors.lastname: Held
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Switzerland; Department of Internal Medicine, Zollikerberg Hospital, Zollikon, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Muggensturm
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Switzerland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Strassmann
authors.affiliation: Institute of General Practice and Health Services Research, University of Zurich, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: Zoller
authors.affiliation: Department of General Practice, Academic Medical Center, University of Amsterdam, the Netherlands.
authors.forename: Gerben
authors.initials: G
authors.lastname: Ter Riet
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Switzerland.
authors.forename: Milo A
authors.initials: MA
authors.lastname: Puhan
mesh_terms: D000368:Aged; D015331:Cohort Studies; D000068598:Data Accuracy; D018450:Disease Progression; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology*; D057566:Self Report / Q000592:standards*
keywords: COPD; adjudication committee; end point; exacerbation; outcome measurement error; sample size