Kornitzer 1995.

Study characteristics
Methods	Study design: parallel RCT Country: Belgium Recruitment: worksite volunteers
Participants	374 healthy smokers (> 10 cigarettes per day for > 3 years), motivated to quit 61% men, average age 40, average cigarettes per day 25
Interventions	1) Nicotine patch (12 weeks 15 mg/16‐hour, 6 weeks 10 mg, 6 weeks 5 mg) and nicotine gum (2 mg, as required) 2) Nicotine patch and placebo gum 3) Placebo patch and placebo gum
Outcomes	Sustained abstinence at 12 months Validation: CO < 10 ppm Adverse events: measured at each visit during treatment (6 months)
Notes	This study was supported by Pharmacia Consumer Pharma Conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	See below
Allocation concealment (selection bias)	Low risk	Quote: "randomized list generated by a computer program". Randomisation balanced between companies 2/2/1
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: "The investigator and the subjects were completely blind concerning treatment" Quote: "unblinding was never requested during the whole study"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Withdrawals counted as treatment failures. All analyses conducted on ITT basis. Dropout and withdrawal rates not reported