ABSTRACT
<b>Purpose</b>: With the aim of improving the efficiency of smoking cessation treatment, we analyzed and classified various factors to identify the relationships between the background of patients and effects of treatment, and examine their characteristics.<br><b>Methods</b>: We conducted a questionnaire survey to collect information on the situation of patients, and obtained their treatment data from medical records. Decision tree analysis, a data mining method, was employed to examine these data.<br><b>Results</b>: According to the results of the survey, the smoking cessation rate was 80.4%. The rate was associated with CO concentrations in the breath at the initial examination, nicotine content in cigarettes smoked by patients, and the daily and total number of cigarettes smoked. The smoking cessation rate among patients under emotional stress was 76.2%; the rate was higher when patients were able to reduce their mental stress levels.<br><b>Conclusion</b>: We identified characteristic relationships between the background of patients and the effects of treatment, and they proved to be useful for the improvement of the smoking cessation rate.