Background:
To determine the cost-effectiveness of different smoking cessation interventions in Thailand compared with unassisted cessation in chronic obstructive pulmonary disease (COPD) patients.

Methods:
A cost-effectiveness study was undertaken using a societal perspective. Cohorts of smokers with COPD: male and female aged 35 years who regularly smoke at least 10 cigarettes per day were simulated in a markov model. Interventions were counseling with nortriptyline or bupropion or varenicline. All were compared to counselling in hospital. Incremental cost per quality-adjusted life years (QALYs) gained was calculated. One-way and probabilistic sensitivity analyses were also performed. Annually budget impact analyses were also estimated for five years.

Results:
Based on Thai willingness-to-pay threshold (USD 4848), nortriptyline was the most cost-saving (USD 100) with QALY gained (0.07 QALY). Varenicline is cost-effective (USD 2181 per QALY) while bupropion was not cost-effectiveness (USD 4917 per QALY) when compared to counselling in hospital alone. Probabilistic sensitivity analysis revealed that nortriptyline has very high probabilities (96%) of being cost-saving while varenicline and bupropion are 98% and 90%. The most influential parameter is efficacy of counseling alone. Average annual budget for varenicline, bupropion and nortriptyline are 23 MB, 25 MB and 3 MB, respectively.

Conclusions:
Adding pharmacology treatment to conventional counselling for smoking cessation resulted in cost-saving. The use of nortriptyline appeared to be the most cost-effective smoking cessation option for COPD patients. Promoting smoking cessation especially for patient with COPD will benefit for individual patient and societal perspective. Thai government may consider including smoking cessation program into national COPD clinic.