Kalman 2006.

Study characteristics
Methods	Study design: parallel RCT Country: USA Recruitment: Veterans Admin Medical Centre and community‐based substance abuse treatment facility
Participants	130 smokers (≥ 20 cigarettes per day with history of alcohol dependence and ≥ 2 month abstinence from alcohol and illicit drugs) 84% men, average age 47, average cigarettes per day: 32
Interventions	Dose response trial 1) Nicotine patch (42 mg (2 x 21 mg)) 4 weeks, then tapered for 8 weeks 2) Nicotine patch (21 mg and placebo) for 4 weeks then same tapering as group 1
Outcomes	Abstinence at 36 weeks (26 weeks post‐EOT) (7‐day PPA) Validation: CO < 10 ppm Adverse events: measured during treatment (up to 12 weeks post‐quit date)
Notes	This study was supported by National Institute on Drug Abuse Research Grant R29‐DA11713‐01. GlaxoSmithKline Beecham provided the nicotine patches for this project. Conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated
Allocation concealment (selection bias)	Unclear risk	Quote: "[participants] were randomly assigned".
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Double‐blind for 4 weeks, then open‐label dose tapering phase
Incomplete outcome data (attrition bias) All outcomes	Low risk	10 dropped out before treatment, and 4 excluded for protocol violation. Analyses were ITT, with dropouts reported and counted as failures