Smoking: nicotine replacement therapy helps smokers quit

Clinical bottom line (level 1a)

  1. Smokers who use nicotine replacement therapy compared with control are more likely to quit (NNT = 16 at 6 months) .
  2. Smokers who receive support in addition to nicotine replacement therapy compared with nicotine replacement alone are more likely to stop (NNT = 20 at 6 months) .
  3. Smokers who use 2 forms of nicotine replacement therapy (e.g. gum and patches) compared with 1 form are more likely to stop smoking (NNT = 18 at 6 months) .
  4. Smokers who use 4 mg gum compared with 2 mg gum are more likely to stop smoking (NNT = 12 at 6 months) .
Silagy et al: Cochrane Library 2000; 3 : -
Expires May 2004

The study

Systematic review of all randomised trials of
  • Patients: smoker
  • Intervention: nicotine replacement therapy (gum, patches, nasal spray, inhalers, tablets) compared with placebo, or no treatment, or different doses of nicotine replacement therapy
  • Outcome: stopped smoking

Articles found in ?all languages using Cochrane Tobacco Addiction Group trials register, to April 2000 (search terms: )

Selection criteria: by 2 independent reviewers: see above and below
Appraisal criteria: by 2 independent reviewers: based on outcome measure, method of randomisation, completeness of follow-up
Articles excluded if:
  • follow-up < 6 months
  • cessation rates not reported
100 RCTs found
  • 88 with a non-NRT control
  • 48 using nicotine gum
  • 30 using transdermal nicotine patches
  • 4 using intranasal nicotine spray
  • 4 using inhaled nicotine
  • 2 using nicotine sublingual tablet
  • 4 compared 2 forms of nicotine therapy with one form alone

The evidence

Outcome Time to outcome CER OR
(95% CI)		 NNT
(95% CI)
quit smoking: NRT v. control 6 months 1745/16942
(10.3%)		 1.73
(1.62 to 1.85) 		16
(14 to 19)
quit smoking: gum v. control 6 months 1110/9613
(11.5%)		 1.66
(1.52 to 1.81) 		16
(13 to 20)
quit smoking: transdermal patch v. control 6 months 508/6159
(8.2%)		 1.76
(1.59 to 1.95) 		18
(15 to 23)
quit smoking: intranasal spray v. control 6 months 52/439
(11.8%)		 2.27
(1.31 to 3.20) 		9
(5 to 32)
quit smoking: inhaler v. control 6 months 44/486
(9.1%)		 2.08
(1.43 to 3.04) 		12
(7 to 29)
quit smoking: tablet v. control 6 months 31/245
(12.7%)		 1.73
(1.07 to 2.80) 		14
(6 to 130)
quit smoking: 4 mg gum v. 2 mg gum 6 months 81/430
(18.8%)		 1.59
(1.16 to 2.20) 		12
(7 to 42)
quit smoking: NRT + low-intensity support v. NRT alone 6 months 591/7546
(7.8%)		 1.75
(1.57 to 1.96) 		20
(16 to 25)
quit smoking: NRT + high-intensity support v. NRT alone 6 months 847/6407
(13.2%)		 1.68
(1.53 to 1.84) 		14
(12 to 18)
quit smoking: 2 forms of NRT v. 1 form of NRT 6 months 101/841
(12.0%)		 1.55
(1.17 to 2.05) 		18
(10 to 57)

Citation

  1. Silagy C, Mant D, Fowler G, et al: nicotine replacement therapy for smoking cessation. Cochrane Library 2000; 3 : -
Search Terms: smoking and cessation in Cochrane Library
Contributor: Chris Ball, May 2002
Reviewer:

Clinical Question.
Patient smoker
Intervention or Exposure nicotine replacement therapy
Comparison control
Outcome stopped smoking at 6 months