BACKGROUND: Understanding the trajectories of daily cigarette consumption (CPD) and withdrawal symptoms in quit attempters would help clinicians in tailoring interventions. This study aimed to identify and profile these trajectories and explore the relapse factors in the trajectory groups.
METHODS: This secondary analysis of a randomized clinical trial involved 928 quitters who had just started to receive cessation treatment at baseline. CPD and the Minnesota Nicotine Withdrawal Scale (MNWS) at baseline, 3-month, 6-month, and 12-month follow-ups were used to fit a group-based multi-trajectory model. A model with the highest BIC, with an average posterior probability for each group ≥ 0.7 and group membership ≥ 5%, was selected. Baseline characteristics were compared across the trajectory groups. Breathlessness, cough, and sputum scale (BCSS), EQ-5D-5L, and the subitems of MNWS were analyzed using the linear mixed model and post-hoc tests.
RESULTS: Five trajectory groups emerged: abstainers (57.5%), reducers (8.6%), late relapsers (6.1%), slow early relapsers (16.6%), and rapid early relapsers (11.2%). Compared to abstainers, reducers reported a higher urge to smoke at the 3-month follow-up, late Relapsers reported a higher urge to smoke, depressed mood, and anxiety at 6 months, and rapid early relapsers scored higher in all MNWS subitems (excluding the urge to smoke and increased appetite), lower EQ-5D-5L scores and lower confidence in quitting at baseline and elevated BCSS at all follow-ups. Rapid early relapsers had the highest CPD (~30) before treatment and FTND among groups.
CONCLUSIONS: To sustain long-term abstinence, treatment should extend beyond 8 weeks, as over 40% of quit attempters relapsed within a year. Due to the heterogeneity of withdrawal symptoms in quitters, personalized and long-term treatment to prevent relapses was warranted.