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Table 4 Results of the per protocol analysis after two years of follow-up according to type of intervention for the variable 'tobacco consumption'

From: Randomised clinical trial of an intensive intervention in the primary care setting of patients with high plasma fibrinogen in the primary prevention of cardiovascular disease

Proportion of smokers Intensive intervention Standard intervention Difference of proportions p valuea
Before 31.9% 26.8% 5.1% 0.372
After 19.4% 22.1% 2.7% 0.669
Before-after difference 12.5% 4.7%   
95% CI 7. 0-18. 2 1.0-8.4   
p valueb 0.016 0.0001   
  1. CI confidence interval
  2. a Difference between groups, calculated by means of Χ2 (comparison of proportions in independent groups)
  3. b Difference between groups calculated using McNemar test (comparison of proportions with paired data)