18. Opioids versus placebo: risk ratio and number needed to treat for an additional harmful outcome (NNTH) for specific adverse events.
| Adverse event | Studies | Participants | Statistical method | Risk ratio | NNTH |
| Anorexia | 1 | 330 | Risk Ratio (M‐H, Fixed, 95% CI) | 13.64 (0.77, 240.21) | ‐ |
| Constipation | 4 | 4255 | Risk Ratio (M‐H, Random, 95% CI) | 2.23 (1.39, 3.59) | 16.82 (13.20, 23.19) |
| Diarrhoea | 1 | 313 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.55 (0.69, 9.43) | ‐ |
| Dizziness | 4 | 4130 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.76 (2.15, 3.55) | 13.55 (11.15, 17.28) |
| Drowsiness, sleepiness, somnolence, or anergia | 3 | 3856 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.89 (2.19, 3.83) | 15.26 (12.34, 20.00) |
| Fatigue | 1 | 1589 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.96 (1.27, 3.03) | 28.54 (17.48, 77.71) |
| Gastrointestinal (unspecified) | 1 | 98 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.77 (0.90, 3.47) | ‐ |
| Headache | 1 | 313 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.78 (0.33, 1.84) | ‐ |
| Hot flushes | 1 | 593 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.83 (1.03, 7.75) | 32.60 (16.95, 421.76) |
| Increased sweating | 1 | 1350 | Risk Ratio (M‐H, Fixed, 95% CI) | 16.05 (3.86, 66.69) | 22.46 (16.37, 35.78) |
| Infection | 2 | 631 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.87 (0.47, 1.61) | ‐ |
| Nausea | 3 | 4346 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.46 (2.08, 2.92) | 8.00 (6.88, 9.56) |
| Nervous system disorders (unspecified) | 1 | 98 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.50 (0.95, 6.56) | ‐ |
| Pruritus | 1 | 2865 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.74 (1.28, 2.36) | 27.44 (18.25, 55.27) |
| Sinusitis | 1 | 318 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.56 (0.52, 4.67) | ‐ |
| Vomiting | 2 | 3368 | Risk Ratio (M‐H, Fixed, 95% CI) | 4.29 (2.90, 6.34) | 14.70 (12.10, 18.72) |
| Xerostomia | 1 | 1668 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.10 (0.47, 2.57) | ‐ |
CI: confidence interval M‐H: Mantel‐Haenszel method of meta‐analysis