Comparison 4. Combination versus single‐form NRT.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
4.1 Smoking cessation	16	12169	Risk Ratio (M‐H, Fixed, 95% CI)	1.27 [1.17, 1.37]
4.1.1 Combination NRT versus patch alone	13	9552	Risk Ratio (M‐H, Fixed, 95% CI)	1.24 [1.13, 1.37]
4.1.2 Combination NRT versus fast‐acting NRT alone	6	2364	Risk Ratio (M‐H, Fixed, 95% CI)	1.30 [1.09, 1.54]
4.1.3 Combination NRT versus choice of single form NRT (patch or fast‐acting)	1	253	Risk Ratio (M‐H, Fixed, 95% CI)	5.16 [1.18, 22.59]
4.2 Any cardiac adverse event	2	656	Risk Ratio (M‐H, Fixed, 95% CI)	0.66 [0.22, 2.05]
4.3 Overall serious adverse events	5	2888	Risk Ratio (M‐H, Fixed, 95% CI)	4.44 [0.76, 25.85]
4.3.1 Combination NRT versus patch alone	4	2313	Risk Ratio (M‐H, Fixed, 95% CI)	11.45 [0.64, 205.90]
4.3.2 Combination NRT versus fast‐acting NRT alone	2	575	Risk Ratio (M‐H, Fixed, 95% CI)	1.00 [0.06, 15.88]
4.4 Treatment withdrawals	5	3070	Risk Ratio (M‐H, Fixed, 95% CI)	1.12 [0.57, 2.20]
4.4.1 Combination NRT versus patch alone	5	1982	Risk Ratio (M‐H, Fixed, 95% CI)	2.32 [0.99, 5.40]
4.4.2 Combination NRT versus fast‐acting NRT alone	2	1088	Risk Ratio (M‐H, Fixed, 95% CI)	0.14 [0.02, 1.08]