Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Postoperative pulmonary infections
RCT	120 people who smoked daily and were scheduled for hip or knee replacement In review	Pulmonary infection 0% with smoking-cessation intervention 0% with usual care	Significance not assessed Low rate of pulmonary infection is consistent with the inherent low risk for postoperative pulmonary infections associated with elective hip or knee replacement
RCT	60 people who smoked daily, undergoing colorectal surgery In review	Postoperative pneumonia (verified by radiograph) 3/27 (11%) with smoking-cessation programme started 2–3 weeks before surgery 4/30 (13%) with control (normal smoking habits before surgery)	Reported as not significant P value not reported The RCT may have been too small to detect a clinically important difference between groups		Not significant