Effect estimates, event rates, and NNTs of meta-analyses examining medical cannabinoids versus placebo or other antiemetics for nausea and vomiting in chemotherapy (or in palliative patients for Mücke et al19)
| SYSTEMATIC REVIEW | OUTCOME (COMPARISON) | NO. OF RCTS (NO. OF PARTICIPANTS) | AUTHORS’ META-ANALYSIS RESULT (95% CI), HETEROGENEITY | META-ANALYSIS RE-ANALYZED (95% CI), HETEROGENEITY | CANNABINOID EVENT RATE, % | CONTROL EVENT RATE, % | NNT |
|---|---|---|---|---|---|---|---|
| Whiting et al, 20152 | Nausea and vomiting—complete response (vs placebo) | 3 (102) | OR = 3.82 (1.55 to 9.42), I2 = 0% | RR = 2.43 (1.30 to 4.52), I2 = 0% | 47 | 20 | 4 |
| Smith et al, 201525 | Absence of nausea and vomiting (vs placebo) | 3 (288) | RR = 2.86 (1.76 to 4.65), I2 = 0% | NA | 37 | 12 | 4 |
| Patient preference (vs placebo) | 2 (256) | RR = 4.82 (1.74 to 13.36), I2 = 69% | NA | 72 | 18 | 2 | |
| Absence of nausea and vomiting (vs prochlorperazine) | 4 (414) | RR = 2.00 (0.74 to 5.38), I2 = 60% | NA | 20 | 11 | NS | |
| Patient preference (vs other drugs) | 9 (799) | RR = 2.76 (1.88 to 4.03), I2 = 61% | NA | 63 | 19 | 3 | |
| Mücke et al, 201619 | Improvement in nausea and vomiting symptoms (vs placebo)* | 2 (307) | SMD = 0.20 (−0.03 to 0.44), I2 = 0% | NA | NA | NA | NA |
| Machado Rocha et al, 200826 | Nausea and vomiting within 1 d of chemotherapy (dronabinol vs placebo) | 2 (185) | RR = 0.47 (0.19 to 1.16), I2 = 91% | NA | 40 | 87 | NS |
| Nausea and vomiting within 1 d of chemotherapy (dronabinol vs neuroleptics) | 5 (325) | RR = 0.67 (0.47 to 0.96), I2 = 79% | NA | 52 | 80 | 4 | |
| Nausea and vomiting within 1 d of chemotherapy (nabilone vs neuroleptics) | 6 (277) | RR = 0.88 (0.72 to 1.08), I2 = 64% | NA | 75 | 85 | NS | |
| Tramèr et al, 200127 | Control of nausea (vs placebo) | 4 (231) | RelR = 1.21 (1.03 to 1.42), I2 = NR | NA | 70 | 57 | 8 |
| Control of vomiting (vs placebo) | 4 (231) | RelR = 1.84 (1.42 to 2.38), I2 = NR | NA | 66 | 36 | 4 | |
| Control of nausea (vs antiemetic) | 7 (422) | RelR = 1.38 (1.18 to 1.62), I2 = NR | NA | 59 | 43 | 7 | |
| Control of vomiting (vs antiemetic) | 6 (395) | RelR = 1.28 (1.08 to 1.51), I2 = NR | NA | 57 | 45 | 9 | |
| Patient preference (vs placebo) | 4 (404) | RelR = 5.67 (3.95 to 8.15), I2 = NR | NA | 76 | 13 | 2 | |
| Patient preference (vs antiemetic) | 14 (1212) | RelR = 2.39 (2.05 to 2.78), I2 = NR | NA | 61 | 26 | 3 | |
| All studies | Control of nausea and vomiting (vs placebo) | 7 (500) | NA | RR = 3.60 (2.55 to 5.09), I2 = 18% | 47 | 13 | 3 |
| Control of nausea and vomiting (vs antiemetics) | 14 (1022) | NA | RR = 1.85 (1.18 to 2.91), I2 = 60% | 31 | 16 | 7 |
NA—not applicable, NNT—number needed to treat, NR—not reported, NS—not significant, OR—odds ratio, RCT—randomized controlled trial, RelR—relative risk, RR—risk ratio, SMD—standardized mean difference.
↵* This was for palliative patients (1 HIV RCT and 1 refractory cancer pain RCT).