A Cochrane review included 58 studies. A nursing intervention compared to a control or to usual care was found to increase the likelihood of quitting (RR 1.29; 95% CI 1.21 to 1.38, 35 studies, over 22 000 participants; high heterogeneity, I²=50%). In a subgroup analysis there was no evidence that high-intensity interventions or interventions with additional follow-up were more effective than lower intensity or interventions with additional follow-up.
Comment: The quality of evidence is downgradedby limitations in study quality (unclear allocation concealment and incomplete outcome data in half of the studies).