title: Validation of smoking cessation self-reported by patients with chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  The present study reports on the biochemical validation of the self-reported smoking status of patients with chronic obstructive pulmonary disease (COPD). The objective is to establish the proportion of overestimation of self-reported success rates.
  
  
  METHODS
  A cross-sectional smoking-status validation study including 60 patients with COPD who reported that they had stopped smoking. In the analysis of urine samples, a cut-off point of 50 ng/mL of cotinine was used.
  
  
  RESULTS
  At the time of biochemical validation, 55 patients reported that they had quit smoking while five patients resumed smoking. Smoking status was biochemically confirmed for 43 patients (78%) and 12 patients (22%) were classified as smokers. The sensitivity of the self- report of smoking was 29% and the specificity was 100%.
  
  
  CONCLUSIONS
  Many primary care patients with COPD do not provide valid information on their smoking status, which hamper adequate therapeutic interventions. Integration of biochemical validation in daily care could overcome this problem, but may harm the doctor-patient relationship.
authors.affiliation: IQ Healthcare, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. s.r.hilberink@hetnet.nl
authors.forename: Sander R
authors.initials: SR
authors.lastname: Hilberink
authors.forename: Johanna E
authors.initials: JE
authors.lastname: Jacobs
authors.forename: Sanne
authors.initials: S
authors.lastname: van Opstal
authors.forename: Trudy
authors.initials: T
authors.lastname: van der Weijden
authors.forename: Janine
authors.initials: J
authors.lastname: Keegstra
authors.forename: Pascal Lj
authors.initials: PLj
authors.lastname: Kempers
authors.forename: Jean Wm
authors.initials: JW
authors.lastname: Muris
authors.forename: Richard Ptm
authors.initials: RP
authors.lastname: Grol
authors.forename: Hein
authors.initials: H
authors.lastname: de Vries