Schuurmans 2004.

Study characteristics
Methods	Study design: parallel RCT Country: South Africa Recruitment: community volunteers
Participants	200 smokers 56% men, average age 43, average cigarettes per day: 23 to 26
Interventions	1) Pretreatment with nicotine patch for 2 weeks prior to quit date. Then active patch (15 mg) for 12 weeks including weaning. 4 sessions of counselling over 10 weeks 2) Pretreatment with placebo patch. Then active patch as for group 1
Outcomes	Sustained abstinence at 6 months Validation: CO < 10 ppm at each visit Adverse events: measured at all follow‐up visits to 6 months (treatment duration 12 weeks)
Notes	This study was supported by a grant from the Swiss Science Foundation (MMS). Conflicts of interest: Pfizer provided medication and support with data analysis.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "a computer‐generated list"
Allocation concealment (selection bias)	Low risk	Quote: "Numbering of identical boxes containing patches was carried out prior to the study by a person not involved in the study"
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: "The treatment code was broken only after the last follow‐up visit had been completed and the data recorded"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Dropouts fully recorded at all stages, ITT analyses used and participants lost to follow‐up counted as smokers