Summary of findings 3. Summary of findings group 3: other comparisons.
| Group 3: other comparisons | ||||||
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Patient or population: participants at risk of high altitude illness Settings: high altitude (including simulated; Chile, China, Nepal, USA) Intervention: ginkgo biloba, acetazolamide + ginkgo biloba, acetazolamide, acetazolamide+ medroxyprogesterone Comparison: acetazolamide, ginkgo biloba, medroxyprogesterone | ||||||
| Comparison: outcome | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of Participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| control group | Intervention group | |||||
| Ginkgo biloba versus acetazolamide: risk of AMS | Not estimable | Not estimable | RR ranged from 0.11 to 2.97 | 378 (3 studies) | ⊕⊕⊝⊝ Low1 | 2 studies reported 102 events of paraesthesia: 92/176 (52.2%) with acetazolamide versus 10/178 (5.6%) with ginkgo biloba (RR 0.11, 95% CI 0.06 to 0.20). 1 study reported one event of polyuria: 1/9 (11.1%) with acetazolamide versus 0/10 (0%) with ginkgo biloba (RR 3.30, 95% CI 0.15 to 72.08). No events of HAPE or HACE occurred in 3 studies. |
| Acetazolamide + ginkgo biloba versus ginkgo biloba: risk of AMS | 274 per 1000 | 118 per 1000 (71 to 194) |
RR 0.43 (0.26 to 0.71) |
311 (1 study) |
⊕⊕⊝⊝ Low2 | 1 study reported 103 events of paraesthesia: 93/154 (60.3%) with acetazolamide plus ginkgo biloba versus 10/157 (6.3%) with ginkgo biloba alone (RR 9.48, 95% CI 5.14 to 17.51). No events of HAPE or HACE occurred in 3 studies. |
| Acetazolamide + ginkgo biloba versus acetazolamide: risk of AMS | 92 per 1000 | 117 per 1000 (60 to 227) |
RR 1.27 (0.65 to 2.46) |
306 (1 study) |
⊕⊕⊝⊝ Low2 | 1 study reported 178 events of paraesthesia: 93/154 (60.3%) with acetazolamide plus ginkgo biloba versus 85/152 (55.9%) with acetazolamide alone (RR 1.08, 95% CI 0.89 to 1.31). No events of HAPE or HACE occurred in 3 studies. |
| Acetazolamide versus medroxyprogesterone: risk of AMS | 500 per 1000 | 500 per 1000 (160 to 1000) |
RR 1.00 (0.32 to 3.10) |
12 (1 study) |
⊕⊕⊝⊝ Low3,4 | No studies reported on adverse effects, or risk of HAPE or HACE |
| Acetazolamide + medroxyprogesterone versus medroxyprogesterone: risk of AMS | 500 per 1000 | 665 per 1000 (250 to 1000) |
RR 1.33 (0.50 to 3.55) |
12 (1 study) |
⊕⊕⊝⊝ Low3,4 | No studies reported on adverse effects, or risk of HAPE or HACE |
| Acetazolamide + medroxyprogesterone versus acetazolamide: risk of AMS | 500 per 1000 | 665 per 1000 (250 to 1000) |
RR 1.33 (0.50 to 3.55) |
12 (1 study) |
⊕⊕⊝⊝ Low3,4 | No studies reported on adverse effects, or risk of HAPE or HACE |
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; RR: risk ratio; OR: odds ratio | ||||||
| GRADE Working Group grades of evidence High quality: further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: we are very uncertain about the estimate. | ||||||
1 Quality of evidence downgraded by two levels due to unclear or high risk of performance and detection bias, as well as inconsistency
2. Quality of evidence downgraded by two levels due to unclear or high risk of performance, detection and attrition bias
3. Quality of evidence downgraded by one level due to unclear selection, performance, detection and other bias
4 Quality of evidence downgraded by one level for imprecision: optimal information size not reached