Determinants of successful smoking cessation in outpatient settings: A comparative analysis of varenicline and free program interventions.

Introduction: Smoking cessation is a significant challenge, and various factors influence the success rates. Understanding the factors affecting cessation outcomes can guide more effective intervention strategies. This study compares the efficacy of a general outpatient cessation program versus a free cessation program, with subgroup analyses based on medication type (bupropion vs varenicline), aiming to identify factors associated with successful smoking cessation in outpatient settings.

Methods: We analyzed data from 356 patients visiting our smoking cessation clinic between January 2018 and June 2022, with random allocation into two groups via computerized random number table upon enrollment: Group A (general outpatient intervention, n=188) and Group B (free cessation program, n=168). Both groups were further subdivided based on the use of bupropion (A1, B1) or varenicline (A2, B2). Factors such as demographic data, nicotine dependence, smoking cessation confidence, exhaled carbon monoxide, and smoking cessation success (7-day point prevalence abstinence rate [PPAR] and 3-month continuous quitting rate [CQR]) were analyzed. To ensure comprehensive results, we performed an intention-to-treat (ITT) analysis, including participants who dropped out or did not complete the study as failures in the smoking cessation outcome.

Results: There were no significant differences between groups A and B in demographics, smoking behavior, or medication, except for occupation and duration of cigarette smoking. Group B had lower nicotine dependence but comparable smoking cessation outcomes to Group A. Factors associated with successful cessation included being older, married, employed full-time, smoking ≤20 cigarettes/day, and using varenicline. The CQR of Group A2 was 9.36% higher than that of Group A1. The PPAR and CQR of Group B2 were 16.66% and 17.93% higher than those of Group B1, respectively. However, there were no significant differences in PPAR and CQR between Group A2 and Group B2.

Conclusions: Varenicline use, specific sociodemographic characteristics (aged >50 years, married, full-time employment), and less severe smoking behavior (≤20 cigarettes/day, ≤25 years duration, ≤600 pack-year) are key determinants of successful smoking cessation in outpatient settings. Varenicline use was associated with significantly higher cessation rates compared to bupropion within both intervention models. The free program incorporating varenicline (B2) demonstrated particularly high success rates.