Lindström 2008.

Methods	Country: Sweden Randomized controlled trial
Participants	117 daily smokers undergoing elective surgery for primary hernia repair, laparoscopic cholecystectomy and hip or knee prosthesis.
Interventions	Intervention: weekly sessions, face‐to‐face or by telephone, with a trained smoking cessation counsellor and NRT 4 weeks pre‐ and 4 weeks postoperatively. Control: Standard care.
Outcomes	Smoking cessation from 3 weeks before to 4 weeks after surgery, and at 1 year (not validated). Postoperative complications requiring intervention within 30 days postoperatively. Wound complications requiring intervention within 30 days postoperatively.
Notes	Smoking cessation was validated by CO in exhaled air.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Stratified block randomization.
Allocation concealment (selection bias)	Low risk	Opaque sealed envelopes.
Blinding (performance bias and detection bias) All outcomes	High risk	Outcomes assessed by study nurses who were not blinded and by the study physicians who were unaware of group allocation. No blinding of participants or personnel.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No losses to 30‐day follow‐up. 7/48 intervention and 3/54 controls lost to 12‐month follow‐up.
Selective reporting (reporting bias)	Low risk	Reports all prespecified outcomes.
Other bias	Low risk