Objectives To develop and evaluate, in a primary care setting, a computerised system for generating tailored letters about smoking cessation.
Design Randomised controlled trial.
Setting Six general practices in Aberdeen, Scotland.
Participants 2553 smokers aged 17 to 65.
Interventions All participants received a questionnaire asking about their smoking Participants subsequently received either a computer tailored or a non-tailored, standard letter on smoking cessation, or no letter.
Main outcome measures Prevalence of validated abstinence at six months; change in intention to stop smoking in the next six months.
Results The validated cessation rate at six months was 3.5% (30/857) (95% confidence interval 2.3% to 4.7%) for the tailored letter group, 4.4% (37/846) (3.0% to 5.8%) for the non-tailored letter group, and 2.6% (22/850) (1.5% to 3.7%) for the control (no letter) group. After adjustment for significant covariates, the cessation rate was 66% greater (-4% to 186%; P = 0.07) in die non-tailored letter group than that in the no letter group. Among participants who smoked < 20 cigarettes per day, the cessation rate in the non-tailored letter group was 87% greater (0% to 246%; P = 0.05) than that in the no letter group. Among heavy smokers who did not quit, a 76% higher rate of positive shift in "stage of change" (intention to quit within a particular period of time) was seen compared with those who received no letter (11% to 180%; P = 0.02). The increase in cost for each additional quitter in the non-tailored letter group compared with the no letter group was <pound>89.
Conclusions In a large general practice, a brief non-tailored letter effectively increased cessation rates among smokers. A tailored letter was not effective in increasing cessation rates but promoted shift in movement towards cessation ("stage of change") in heavy smokers. As a pragmatic tool to encourage cessation of smoking, a mass mailing of non-tailored letters from general practices is more cost effective than computer tailored letters or no letters.