Kupecz 1996.

Study characteristics
Methods	Study design: prospective quasi‐experimental design Country: USA Recruitment: smokers attending for smoking cessation treatment at the Veterans’ Affairs Medical Center in Denver between September 1992 and March 1993 (following self‐enrolment or referral by physician or nurse) were invited to participate
Participants	45 smokers: motivated to quit 94.7% men; average age: 50.2 years; average FTND: 7; 69% living in a smoking household environment, average pack/year history: 47.2 years
Interventions	1) Nicotine patch treatment for 10 weeks (21 mg/day for 6 weeks, then 14 mg/day for 2 weeks, then 7 mg/day for 2 weeks) 2) Nicotine gum: 2 mg pieces (chewed for 20 minutes) ad libitum for 12 weeks, then an individualised tapering schedule with the goal of discontinuing therapy within the next 12 weeks All participants began the above treatment on their quit date and attended 4 weekly sessions, which included contract negotiation, positive reinforcement, relaxation exercises, visual imagery and group support. Following the cessation programme, participants attended 7 follow‐up sessions.
Outcomes	PPA (defined as not smoking at time of asking) 52‐week follow‐up, validated by exhaled CO < 8 ppm Other abstinence measures: PPA at 6, 12 and 26 weeks (CO‐validated) Adverse events: recorded at each session or follow‐up. Note: follow‐up was to 1 year, and treatment was to 24 weeks
Notes	ITT numbers are not available. There were 7 dropouts after randomisation, but how these were split across study arms is not reported, making it impossible to perform an ITT analysis. There was no response to a request for the numbers randomised. Funding and conflicts of interest not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	It appears that treatment (gum or patch) was assigned randomly to the month of recruitment and then all participants recruited in that month received the allotted treatment rather than allocating treatment to individual participants. Quote: “A prospective quasi‐experimental design was employed…” Quote: “During this study, patients were assigned to nicotine gum or a nicotine patch on random months.” Quote: “A random number table was used to assign which product would be used. Each month, the nicotine patch or nicotine gum was randomly assigned to participants in that group by blindly selecting the treatment from an envelope that contained both options.”
Allocation concealment (selection bias)	Unclear risk	Quote: “Each month, the nicotine patch or nicotine gum was randomly assigned to participants in that group by blindly selecting the treatment from an envelope that contained both options.” It is unclear whether the treatment for that month was selected before or after the participants had been enrolled for the month. If the treatment was allocated pre‐enrolment, then this could have influenced allocation of individuals.
Blinding (performance bias and detection bias) All outcomes	High risk	Not placebo‐controlled; participants were aware which intervention they were receiving
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Quote: “Seven dropped out prior to completing the program”