Work

Decision-tree analysis of characteristics associated with 6-month smoking abstinence in Taiwan

Year: 2026

Type: article

Abstract: Objective To identify smoker profiles associated with higher 6-month smoking abstinence using decision-tree analysis in a nationwide cessation service. Design Retrospective nationwide service-based study. Exploratory classification and regression tree (CART) analysis described subgroups with different observed abstinence probabilities, while multivariable logistic regression using generalised estimating equations (GEE) estimated adjusted associations accounting for repeated annual records within service users. Setting Taiwan’s Second-Generation Smoking Cessation Service Programme, a nationwide, multi-institutional smoking cessation service programme across multiple levels of care (2012–2022). Participants 906 827 person-year records from 646 851 service users with valid 6-month abstinence outcomes aggregated by service user and calendar year. Annual records summarised service use, baseline characteristics and the last valid 6-month abstinence outcome. Exposures Variables included age, sex, smoking-related characteristics, service use, prescribed pharmacotherapy duration, calendar year, region, urbanisation, institution level and health professional type. Primary outcome measures Self-reported 7-day point-prevalence abstinence assessed at 6 months. Results In CART, the highest observed abstinence probability was 0.59 among records with at least 6 weeks of prescribed pharmacotherapy and time to first cigarette >30 min after waking (16% of records). Among records with at least 6 weeks of prescribed pharmacotherapy, time to first cigarette of ≤30 min and <20 cigarettes/day defined a large subgroup with an observed probability of 0.53 (39%). In adjusted GEE analysis, each 1-point increase in the Fagerström Test for Nicotine Dependence total score was associated with lower odds of abstinence (OR 0.92, 95% CI 0.91 to 0.92). Conclusions Exploratory CART identified person-year subgroups with differing observed abstinence probabilities. Longer recorded prescribed pharmacotherapy duration and lower overall nicotine dependence were generally associated with higher odds of abstinence in adjusted GEE analyses, but these observational findings do not establish causal effects or clinically validated treatment thresholds.

Source: BMJ Open

DOI: 10.1136/bmjopen-2025-112023