Summary of findings 1. Combination compared to single‐form nicotine replacement therapy for smoking cessation.
| Combination compared to single‐form nicotine replacement therapy (NRT) for smoking cessation | ||||||
| Patient or population: people who smoke Setting: any; studies conducted in: Australasia, China, Europe, USA Intervention: combination NRT (nicotine patch plus a fast‐acting form of NRT) Comparison: single‐form NRT | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with single‐form NRT | Risk with combination NRT | |||||
| Smoking cessation | Study population | RR 1.27 (1.17 to 1.37) | 12,169 (16 RCTs) | ⊕⊕⊕⊕ Higha | ‐ | |
| 137 per 1000 | 174 per 1000 (160 to 187) | |||||
| Overall serious adverse events | Study population | RR 4.44 (0.76 to 25.85) | 2888 (5 RCTs) | ⊕⊕⊝⊝ Lowb | ‐ | |
| 1 per 1000 | 3 per 1000 (1 to 18) | |||||
| Treatment withdrawals | Study population | RR 1.12 (0.57 to 2.20) | 3070 (5 RCTs) | ⊕⊝⊝⊝ Very lowb,c | ‐ | |
| 12 per 1000 | 14 per 1000 (7 to 27) | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; NRT: nicotine replacement therapy; RCT: randomised controlled trial; RR: risk ratio | ||||||
| GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. | ||||||
aWe rated most studies at low or unclear risk of bias. We did not downgrade the certainty of the evidence, as limiting the analysis only to studies we judged to be at low risk of bias resulted in a consistent effect estimate and 95% confidence interval. bDowngraded by two levels due to imprecision: fewer than 100 events overall and confidence intervals encompass clinically significant harms as well as clinically significant benefits. cDowngraded one level due to inconsistency: moderate unexplained statistical heterogeneity (I2 = 73%).