COPD: smoking cessation intervention decreases symptoms.

Clinical bottom line (level 1b)

  1. Patients with early chronic obstructive pulmonary disease who are given a smoking cessation intervention, are less likely to have a cough for at least 3 months a year than those given usual care (NNT = 6 at 5 years) .
  2. Patients given smoking cessation intervention are less likely to have phlegm for at least three months a year than those given usual care (NNT = 8 at 5 years) .
  3. Patients given an intervention are less likely to have any wheezing (NNT = 12 at 5 years) .
  4. Patients given an intervention are less likely to have any dyspnea (NNT = 20 at 5 years) .
Kanner et al: American Journal of Medicine 1999; 106 : 410-416
Expires January 2003

The study

Double-blinded ?concealed randomised trial with intention-to-treat
Setting: 10 clinical centres, North American

5887 patients (aged range 35 to 60 years; mean 48, 63% male) current smokers deemed to be at high risk of chronic obstructive pulmonary disease (FEV1/FVC <0.70 and FEV1 55% to 90% of predicted

Excluded if
  • disease or condition which may affect participation during the 5 year follow-up
  • regularly taking prescribed medications that could affect lung function
  • did not agree to enter a behavioural-modification programd designed to help them stop smoking

    Control Group: (n = 1964, 1885 analysed): usual care (no intervention other than advice to stop smoking)
    Experimental Group: (n = 1962, 1903 analysed): smoking intervention plus inhaled placebo. The intervention was a behavioural-intervention program which consisted of a strong physician's message and a gropu orientation meeting led by trained interventionists. This was followed by an intensive 12 session group intervention program during a 10 week period.
    Experimental Group: (n = 1961, 1902 analysed): smoking intervention plus inhaled ipratropium bromide
    Nicotine gum was given at no cost to all participants who thought that it may help them.
    97% followed for 5 years
    Outcome notes:
    • cough for at least 3 months of the year : Symptoms were recorded using the standard American Thoracic Society Society respiratory symptom questionnaire with minor modifications.

    The evidence

    Outcome Time to outcome CER EER RRR
    (95% CI)    		 ARR
    (95% CI)    		 NN T
    (95% CI)
    cough for at least 3 months of the year weeks 877
    (46.7%)    		 1088
    (29.2%)    		 37.0%
    (33.0% to 42.0%)    		 17.5%
    (14.8% to 20.2%)    		 6
    (5 to 7)
    phlegm for at least 3 months of the year 5 years 701
    (37.3%)    		 931
    (25.0%)    		 33.0%
    (27.0% to 38.0%)    		 12.3%
    (9.73% to 14.9%)    		 8
    (7 to 10)
    wheezing at any time 5 years 1011
    (53.8%)    		 1706
    (45.8%)    		 15.0%
    (10.0% to 19.0%)    		 8.03%
    (5.26% to 10.8%)    		 12
    (9 to 19)
    dyspnea at any time 5 years 720
    (38.3%)    		 1238
    (33.2%)    		 13.0%
    (7.00% to 19.0%)    		 5.10%
    (2.43% to 7.77%)    		 20
    (13 to 41)

  • According to the study, ipratropium had no clear effect, so results for intervention with and without ipratropium were combined.
  • The number of patients with each symptom were both those who did and those who did not report the symptom at baseline, combined for this appraisal.

    Citation

    1. Kanner RE, Connett JE, Williams DE, et al: Effects of randomized assignment to a smoking cessation intervention and changes in smoking habits on respiratory symptoms in smokers with early chronic obstructive pulmonary disease: The lung health study. American Journal of Medicine 1999; 106 : 410-416
    Contributor: Clare Wotton, January 2000
    Reviewer:

    Clinical Question.
    Patient COPD
    Intervention or Exposure smoking cessation intervention
    Comparison no intervention
    Outcome cough, phlegm, wheezing and dyspnea