Fig 2. Flow chart of study participants.

Among 949 patients who initially visited smoking cessation clinics, 420 underwent smoking cessation therapy using varenicline for 12 weeks; all these patients ceased smoking in the short term. Twenty patients who used acid suppressive drugs, had peptic ulcer disease, or had a history of upper GI surgery were excluded, and 209 patients did not complete the survey 1 year later. Of 191 patients who completed the survey 1 year after attempted smoking cessation, 141 patients achieved smoking cessation (success group) and 50 did not (failure group).