How effective is nicotine replacement therapy in helping people to stop smoking?
Abstract Objective : To assess the efficacy of nicotine replacement therapy in helping people to stop smoking. Design : Analysis of the results of 28 randomised trials of nicotine 2 mg chewing gum, six trials of nicotine 4 mg chewing gum, and six trials of nicotine transdermal patch. Subjects and setting : Subjects were self referred (responding to advertisements or attending anti-smoking clinics) in 20 trials and invited (general practice or hospital patients) in 20. Therapists in self referred trials were generally experienced in helping people stop smoking but not in invited trials. Main outcome measure – Efficacy was defined as difference in percentages of treated and control subjects who had stopped smoking at one year. Results – Efficacy was highly significant (P<0.001) for both gum and patch. Nicotine 2 mg chewing gum had an overall efficacy of 6% (95% confidence interval 4% to 8%), greater in self referred subjects than in invited subjects (11% v 3%). Efficacy depended on the e
