Impact of the intensified follow-up procedure of patients lost to 6-month follow-up after an intensive smoking and nicotine cessation intervention in practice: a cohort study.

Background: Post-intervention follow-up is challenging in research and practice. In tobacco reports, patients with missing follow-up were considered smokers. Based on patient and staff preferences, an add-on intensified follow-up procedure after intensive tobacco and nicotine cessation interventions was developed. This study examined the impact of the new procedure on patients lost to follow-up and compared their cessation status with that of those who completed routine follow-up.

Methods: Between January and February 2023, 2114 patients participated in the Danish STOPbase for Tobacco and Nicotine after providing informed consent. Overall, 1529 (72%) patients completed routine 6-month follow-up interviews, 136 (6%) patients rejected follow-up participation and 449 (21%) patients were lost to follow-up. Of the 449 patients, 225 patients were randomly selected to undergo the new follow-up procedure with repeated information, up to four extra calls, texts and voice messages from known telephone numbers.

Results: Using the new procedure, 143/225 (64%; 95% CI: 61% to 67%) patients completed the follow-up, with a continuous quit rate of 54/225 (24%; 21% to 27%). The lost to follow-up group had a significantly lower continuous cessation rate than the group that completed the routine follow-up: 54/143 (38%; 34% to 42%) and 703/1529 (46%; 45% to 47%), respectively, (p<0.01).

Conclusion: Almost two-thirds of the patients lost to 6-month follow-up completed the intensified follow-up procedure and had substantially lower cessation rates than those completing routine follow-up. However, this finding is clinically relevant, as a high follow-up rate impacts the reliability of outcomes, with loss to follow-up reported on continuous use.