Outcome | Including | Excluding studies with | ||||||||||
All studies | ≥2 high risk of bias | ≥50% attrition | ≤50% compliance | |||||||||
n | Risk ratio (95% CI) | I2 (%) | n | Risk ratio (95% CI) | I2 (%) | n | Risk ratio (95% CI) | I2 (%) | n | Risk ratio (95% CI) | I2 (%) | |
Continuous abstinence | ||||||||||||
Long term | 6 | 2.60 (1.71–3.97) | 41 | 4 | 3.17 (2.05–4.90) | 12 | 6 | 2.60 (1.71–3.97) | 41 | 3 | 2.96 (1.89–4.64) | 14 |
Short term | 5 | 2.49 (0.94–6.56) | 84 | 2 | 5.63 (3.04–10.4) | 35 | 5 | 2.49 (0.94–6.56) | 84 | 2 | 3.86 (1.94–7.66) | 24 |
Point prevalence | ||||||||||||
Long term | 12 | 1.64 (1.08–2.47) | 90 | 7 | 1.65 (0.90–3.03) | 94 | 9 | 1.80 (1.12–2.88) | 88 | 7 | 1.76 (1.31–2.36) | 59 |
Short term | 9 | 1.68 (1.10–2.56) | 83 | 4 | 1.67 (0.77–3.64) | 91 | 9 | 1.68 (1.10–2.56) | 83 | 4 | 2.90 (1.30–6.45) | 76 |
n: number of studies included in the analyses.