Table 1

Characteristics of studies included in the review

Authors	Type of surgery	No. of patients	Preoperative smoking cessation period	Length of follow-up	Clear definition of period of cessation	Cessation validated	Main findings	Percentage risk/relative risk
*Information on the total number of participants in each group not provided.
†The exact number of participants in each group does not appear to match the total number in the sample reported.
CI, confidence interval; CS, current smokers; mths, months; PS, past smokers; NS, non- smokers; QPS, quit post-surgery; RR, relative risk; wks, weeks.
Barrera et al, 2005³⁰	Thoracotomy/ lung cancer resection	300	PS	30 days	Yes	No	No significant increase in pulmonary complications among those who quit within 2 months and CS. Incidence of pneumonia was lower in NS compared to PS or CS but there was no significant difference between PS and CS	Total complications
		300	<2 mths (13%)					PS = 19%
			>2 mths (62%)					RQ = 23%
			CS (4%)					NS = 8%
			NS (21%)					Pneumonia
								PS = 10%
								RQ = 15%
								NS = 3%
								Atelectasis
								PS = 5%
								RQ = 3%
								NS = 0%
								Pulmonary embolism
								PS = 2%
								RQ = 3%
								NS = 2%
								Respiratory failure
								PS = 1%
								RQ = 3%
								NS = 0%
								Mean length of stay
								CS = 9 days
								PS = 8 days
								RQ = 8 days
								NS = 6 days
Bluman et al, 1998³²	General, orthopaedic, cardiac	410	PS (46%)	Not stated	Yes	No	CS had a 6×-increased risk of pulmonary complications. There was no significant increase in risk of pulmonary complications in PS in comparison to NS. Reducing cigarette consumption <1 month preoperatively did not reduce the risk of pulmonary complications	Atelectasis or worsening
			<1 wk					CS = 8%
			⩾1 wk <2 wks					PS = 7%
			⩾2 wks <4 wks					NS = 0%
			⩾1 mth					Pulmonary infection
			CS reduced <4 wks					CS = 3% PS = 1% N
			CS (34%)					S = 0%
			NS (20%)					Mortality
								CS = 1%
								PS = 1%
								NS = 0%
								Total PCs (95% CI)
								<1 wk = 3.5%; 10.6 (1.6 to 69.6)
								<2 wks = 7.1%; 4.7 (1.2 to 19.0)
								<4 wks = 7.8%; 4.0 (1.0 to 15.7)
								⩾1 mth = 6.4%; 14.2 (3.2 to 63.6)
								CS = 74.5% 1.0

Chang et al, 2000³³	TRAM flap breast reconstruction	718	PS ⩽4 wks (67%)	Not stated	No	No	CS had a higher incidence of complications than NS with no significant differences between NS and PS. Heavier smokers had a higher overall complication risk than lighter smokers	Overall flap complication
			CS (13%)					CS = 31.1%
			NS (67%)					PS = 25.3%
			NS (67%)					NS = 22.6%
Goodwin et al, 2005³⁴	Tissue expander/implant breast reconstruction	515	PS >4 wks (15%)	Not stated	No	No	There were significantly more complications in PS than NS. There was no significant difference in complication rates between PS and CS. There was an 80% increased risk of complications for each pack increase in cigarettes per day	Wound infection
			CS (11%)					CS = 9.1%
			NS (75%)					NS = 2.9%
								Total PCs
								CS = 37.9%
								NS = 15.1%
Hasdai et al, 1997³⁵	Coronary revascularisation	5437	PS >6 mths (42%)	Up to 16 years (average 4.5 years)	No	No	Long-term risk of mortality was 44% greater in CS in comparison to PS. Cessation before or after surgery was beneficial	Mortality QPS = 1.2 (0.87–1.70)
			QPS (8%)					PS = 1.3 (1.14–1.57)
			CS (14%)					NS = 1.0
			NS (37%)					Myocardial infarction
								QPS = 1.4 (0.64 to 3.11)
								PS = 1.28 (0.77 to 2.16)
								NS = 1.0
								Severe angina
								QPS = 0.91 (0.76 to 1.08)
								PS = 0.99 (0.90 to 1.09)
								NS = 1.0

Lavernia et al, 1999³⁶	Unilateral arthroplasty of hip or knee	202	PS <6 weeks	Not stated	No	No	NS combined with PS had significantly shorter surgery duration and needed less anaesthesia than CS. NS combined with PS had significantly shorter surgery duration and needed less anaesthesia than CS	Length of stay
			CS (12%)					CS = 5.4±3.9
			NS (88%)					PS = 5.3±2.7
								NS = 5.1±2.6
								Total PCs
								CS = 16%
								PS = 26.2%
								NS = 21.5%
Levin et al, 2004³⁷	Onlay bone grafts, sinus lift	128	PS >6 mths	Not stated	No	No	Significantly higher incidence of postoperative complications in CS in comparison to NS. No significantly increased risk of complications in PS	Total PCs
			CS:					NS = 23.1%
			Mild <10 per day					CS = 50%
			Heavy ⩾10 per day					No data obtainable for PS
			NS*					No data obtainable for PS
Moore et al, 2005³⁸	Pelvic reconstructive surgery	887	PS ⩾1 mth (26%)	1 mth	No	No	No significant difference in the incidence of postoperative complications in NS and PS	Total PCs PS = 26%
			NS (74%)					NS = 29%
			NS (74%)
Myles et al, 2002³⁹	Ambulatory Surgery	489	PS>28 days (24%)	7 days	No	Yes	PS combined with NS had a significantly lower incidence of coughing, respiratory complications and wound infection than CS	Respiratory CS = 33.5%
			CS (41%)					PS = 34.5%
			NS (35%)					NS = 25.9%
								Wound infection
								CS = 3.7%
								PS = 2.6%
								NS = 0.6%

Warner et al, 1989⁴⁰	Coronary artery bypass graft (CABG)	192	PS (69%)	96 days	Yes	Yes	Smokers quitting <2 months before surgery had a 4× increased risk of pulmonary complications than those quit >2 months before surgery. Smokers who stopped smoking >6 months before surgery had the same risk of complications as NS	Total PCs
			<2 mths					<2 months = 57.1%
			>2 mths					>8 weeks = 11.8%
			CS (9%)					>6 months = 11.1%
			NS (22%)					CS = 33%
			NS (22%)					NS = 11.9%
Woehlck et al, 1999¹⁷	Non-emergency, non-cardiac and non-major vascular surgery	740	PS data included in with NS (62%)	Not stated	No	Yes	CS had more complications than PS or NS	Data unobtainable
Woehlck et al, 1999¹⁷	Non-emergency, non-cardiac and non-major vascular surgery	740	CS (37%)†	Not stated	No	Yes	CS had more complications than PS or NS	Data unobtainable
Yamashita et al, 2004⁴¹	Minor	1008	PS (37%) <1 wk	30 days or up to discharge	Yes	No	CS and PS significantly more likely to have increased intraoperative sputum volume than NS. No significant differences in postoperative complications between PS, CS and NS	Increased sputum; RR (95% CI)
			>1 wk <2 wks >2 wks <2 mths					<1 wk = 22.9%; 2.4 (1.6 to 3.6)
			>2 mths CS (16%)					<2 wks = 22.9%; 2.4 (1.2 to 4.8)
			NS (48%)					<2 mths = 18.8%; 2.0 (0.9 to 4.3)
								>2 mths = 11.0%; 1.2 (0.7 to 2.0)
								CS = 18.2%; 1.9 (1.3 to 3.0)
								NS = 9.3% 1.0
								Total PCs
								>24 hours = 1.4%
								CS = 1.9%
								NS = 1.7%