Summary of findings 1. Heated tobacco use compared with cigarette smoking.
| Heated tobacco use compared with cigarette smoking | ||||||
| Patient or population: people who smoke Setting: USA, Japan, UK, South Korea, Poland Intervention: heated tobacco use Comparison: cigarette smoking | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with cigarette smoking | Risk with heated tobacco use | |||||
| Adverse events – measured by self‐report | Study population | RR 1.03 (0.92 to 1.15) | 1713 (6 RCTs) | ⊕⊕⊝⊝ Lowa,b | — | |
| 235 per 1000 | 242 per 1000 (216 to 270) | |||||
| Serious adverse events – measured by self‐report and medical records | Study population | RR 0.79 (0.33 to 1.94) | 2009 (9 RCTs) | ⊕⊝⊝⊝ Very lowa,c | — | |
| 13 per 1000 | 10 per 1000 (4 to 24) | |||||
| NNAL at follow‐up – measured in urine | — | — | LMD 0.81 lower (1.07 lower to 0.55 lower) | 1959 (10 RCTs) | ⊕⊕⊕⊝ Moderatea | LMD has no units as it is calculated from the logarithm of biomarker measurements. |
| COHb at follow‐up – measured in blood | — | — | LMD 0.74 lower (0.92 lower to 0.52 lower) | 1807 (9 RCTs) | ⊕⊕⊕⊝ Moderatea | LMD has no units as it is calculated from the logarithm of biomarker measurements. |
| *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; COHb: carboxyhaemoglobin; LMD: difference in means of log‐transformed measurements; NNAL: 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol; 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. | ||||||
aDowngraded one level for risk of bias: all studies were at either unclear or high risk of bias. bDowngraded one level for imprecision: confidence intervals contain clinically meaningful benefit and clinically meaningful harm. cDowngraded two levels for imprecision: confidence intervals contain large clinically meaningful benefit and clinically meaningful harm.