Gorecka 2003.

Methods	Design Randomised controlled trial Setting Outpatients
Participants	Inclusion criteria Smokers with spirometry confirmed COPD (airflow limitation (FEV1/FVC < 0.7)) who responded to the invitation for the second spirometry testing (COPD confirmed on 2 spirometry tests done 1 year apart) and who did not stop smoking despite counselling done 1 year prior to the start of the study after the first spirometry. Exclusion criteria None Number randomised Total 70, nicotine patch (NP) 38, bupropion 32 Number followed up Total 69 Age mean (SD): total 55.8 (9.5) Sex n (%) male: total 40 (57) Cigarettes/day mean (SD): total 23.4 (9.1) FTND mean (SD): total 6.5 (2.1) Severity COPD (FEV1/FVC not reported) FEV1% predicted, mean (SD): total 73 (17)
Interventions	Behavioural treatment For all groups counselling by respiratory physician to stop smoking during all 4 visits Pharmacological treatment A. Nicotine patch Transdermal nicotine patch (free of charge) 15 mg/day for 16 hrs every day. Nicotine patch was used for 8 weeks. B. Bupropion Buproprion (free of charge) 300 mg/day (1 x 150 mg for 3 days then 2 x 150 mg daily). Bupropion was used for 7 weeks
Outcomes	Abstinence Prolonged abstinence (did not smoke a single cigarette for a year since the enrolment) at 12 months from start of the intervention. Validation Exhaled CO < 10 ppm
Notes	Funding The study was part of the national program for early detection and prevention of COPD, and medications were provided by pharmaceutical companies; Pharmacia provided the nicotine patch and GlaxoSmithKline provided bupropion Conflicts of interest Not reported CorrespondenceGorecka 2003 was translated. All information was obtained from the translators
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Random sequence method not described
Allocation concealment (selection bias)	Unclear risk	Allocation concealment not described
Blinding of participants and personnel (performance bias) All outcomes	High risk	Presumably no blinding as participants would have known if they were assigned to use a patch or a pill
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	"One person only was not to be contacted at the 1 year final follow‐up phone call.'
Selective reporting (reporting bias)	Low risk	Results for all outcome measures were reported
Other bias	Unclear risk	Participants' and personnel's adherence to the intervention protocol was not described. 13 participants did not come to the first follow‐up visit (at 2 weeks) when they were due to receive the remainder of the medications. Thus, 18.6% did not take medication according to the protocol. Unclear how this number was spread between the 2 treatment groups