Table 1.

Intervention outcomes

Authors	Quality Scorea	Cessation measureb	Cessation criteria	A priori sample size required	Attrition rate%	N experimental	N control	Quit% experimental	Quit% control	d	Post-hoc power c
Anthonisen et al. (1994)	5	CA	Cotinine levels of <20 ng/mL or, if using NRT exhaled CO <10 ppm. Stopped smoking in the initial intervention and maintained this status	4000	3.5	1,961	1,964	20.80	5.20	0.48d	1
Borglykke, Pisinger, Jorgensen, and Ibsen (2008)	6	PP	Self-reported, validated by carbohaemoglobin <2%	NR	0	121	102	29.75	12.75	0.42	0.75
Brandt et al. (1997)	2	PP	Self-reported validated by CO at the final follow-up	NR	6.25	20	25	40	20	0.45	0.43
Christenhusz (2006)	4	CA	Self-reported continuous for 12 months, validated by cotinine <20 ng/mL at 6 and 12 months (must have at least 4 days abstinence for this to occur)	162	6.67	105	105	19.05	8.57	0.31	0.72
Crowley, Macdonald, and Walter (1995)	4	PP	Self-reported abstinence for 24 hr, CO <10 ppm	NR	26.53	18	15e	NR 15.15 total	NR 15.15 total	0e	NC
Efraimsson, Hillervik, and Ehrenberg (2008)	4	PP	‘Do you smoke?’ yes/no	NR	19.23g	16	14	37.5	0	1.06	0.88
Hilberink, Jacobs, Breteler, de Vries, and Grol (2011)	5	PP	Self-reported, did not smoke in the last 7 days, verified by urinary cotinine <50 ng/mL	300	4.3	519	148	7.51	3.38	0.14	0.56
Khdour, Kidney, Smyth, and McElnay (2009)	4h	CA	Self-reported as in the maintenance stage from a stage of change questionnaire at 12 months	160	17.34g	18	19	22.22	10.53	0.32	0.24
Kotz, Wesseling, Huibers, and van Schayck (2009)	5	CA	Abstinence at weeks 5, 26, and 52 validated by urinary cotinine <50 ng/mL	168	15.76	116	68	11.21	5.88	0.19	0.36
Pederson, Wanklin, and Lefcoe (1991)	3	CA	Self-reported quit smoking for 6 months, random sample verified by carboxyhaemoglobin levels in a blood sample	74	21.62	30	28	33.33	21.43	0.27	0.26
Sundblad, Larsson, and Nathell (2008)	3	CA	Self-reported abstinence for the last 6 months. N = 35 CO tested for <8 ppm	NR	18.2	192	199	38.02	10.05	0.7	1
Tashkin et al. (2001)	9	CA	0 cigarettes from weeks 4–26 verified at each clinic visit by exhaled CO ≤10 ppm	400	31.19	204	200	15.69	9.0	0.20	0.64
Tashkin et al. (2011)	9	CA	Self-reported abstinence from weeks 9 to 52, validated at each clinic visit, CO ≤10 ppm	500	33.93	248	251	18.6	5.6	0.41	1
Tønnesen, Mikkelsen, and Bremann (2006)	9	CA	Self-reported abstinence from week 2 to month 12. Verified at each clinic visit by carbon monoxide <10 ppm	268	22.16	185i	185j	14.05	5.41	0.29	0.87
Wagena, Knipschild, Huibers, Wouters, and van Schayck (2005)	9	CA	Self-reported complete abstinence from weeks 4 to 26 after quit date, confirmed by urinary cotinine of ≤60 ng/mL at weeks 4, 12 and 26 post-quit date	300	<5%g	96k	48	25l	8.33	0.38m	0.73
Wilson et al. (2008)	6	CA	Complete cessation for all visits. Verified by exhaled CO ≤10 ppm and salivary cotinine ≤10 ng/mL	303	25.27	56n	35	0	0	0o	NC
Zwar et al. (2012)	6	PP	Smoking status at 12 months, no further detail given		27.41	74	61	14.86	16.39	0.04	0.08

Ne = number in experimental group; Nc = number in control group; NR = not reported; PP = point prevalent; CA = continuous abstinence; CO = carbon monoxide; NC = not calculable; ppm = parts per million.

^aResults from the Delphi list quality assessment (Verhagen et al., 1998)

^bIn studies where both CA and PP were reported, CA was used

^cCalculated post hoc from http://www.danielsoper.com/statcalc/calc49.aspx one-tailed, using total sample size, d, and an alpha level of .05

^dBronchodilator versus usual care

^eControl group only, excluding self-report

^fEstimated, no significant difference between groups

^gFor whole sample

^hMinimization counted as equivalent to randomization

ⁱSum of high and low support with NRT as there were no significant differences between groups

^jSum of high and low support with placebo as there were no significant differences between groups

^kBupropion and nortriptyline

^lTotal quit rate for bupropion and nortriptyline

^mCombined bupropion and nortriptyline versus placebo

ⁿCombined individual and group support groups

^oEstimated 0 quit smoking in either group not reported for smokers only.