Summary of findings 1. Ginkgo biloba compared to placebo for tinnitus.
| Ginkgo biloba compared to placebo for tinnitus | ||||||
| Patient or population: adults with tinnitus Setting: departments of otorhinolaryngology in Brazil, Germany and Turkey and one study conducted by telephone/email Intervention: Ginkgo biloba Comparison: placebo | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo | Risk with Ginkgo biloba | |||||
| Tinnitus symptom severity Assessed with: THI (range: 0 to 100) Follow‐up: 3 to 6 months |
The mean tinnitus symptom severity at 3 to 6 months was 4 | MD 1.35 lower (8.26 lower to 5.55 higher) | — | 85 (2 RCTs) | ⊕⊝⊝⊝ very low1,2,3,4 | Ginkgo biloba may have little to no effect on tinnitus severity compared to placebo, but the evidence is very uncertain. |
| Serious adverse effects (bleeding or seizures) Yes or no Follow‐up: at 3 months |
Study population | — | 1154 (4 RCTs) | ⊕⊕⊝⊝ low5,7 | Ginkgo biloba may result in little to no difference in the risk of serious adverse effects (bleeding or seizures), with zero cases reported in either group. | |
| Zero events in the placebo group | Zero events in the Ginkgo biloba group | |||||
| Tinnitus loudness Assessed with: audiometric loudness matching Follow‐up: at 12 weeks |
The mean tinnitus loudness was 0.8 | MD 4 lower (13.33 lower to 5.33 higher) | — | 73 (1 RCT) | ⊕⊝⊝⊝ very low3,4,6 | Ginkgo biloba may result in little to no difference in tinnitus loudness compared to placebo. |
| Health‐related quality of life Assessed with: GHSI (range: 0 to 100) Follow‐up: 3 months |
The mean quality of life at 3 months was 2.52 | MD 0.58 lower (4.67 lower to 3.51 higher) | — | 60 (1 RCT) | ⊕⊕⊝⊝ low3,5 | Ginkgo biloba may result in little to no difference in quality of life compared to placebo. |
| Other adverse effects (gastrointestinal upset, headache, allergic reaction) Yes or no Follow‐up: at 3 months |
Study population | RR 0.91 (0.52 to 1.60) | 1175 (4 RCTs) | ⊕⊕⊝⊝ low3,5 | Ginkgo biloba may not increase the frequency of other adverse effects (gastrointestinal upset, headache, allergic reaction) compared to placebo. | |
| 41 per 1000 | 37 per 1000 (21 to 66) | |||||
| *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; GHSI: Glasgow Health Status Inventory; MD: mean difference; RCT: randomised controlled trial; RR: risk ratio; THI: Tinnitus Handicap Inventory | ||||||
| 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. | ||||||
1One of the two studies omitted primary outcome data, and had dropout without reason; downgraded by 0.5 level for study limitations. 2Only people over the age of 60 are included in this body of evidence; downgraded by 0.5 level for indirectness. 3Wide confidence interval around the point estimate; small sample size; downgraded by 1 level for imprecision. 4Only a small proportion of the included studies reported on this critical outcome: publication bias is suspected; downgraded by 1 level for publication bias. 5Some of the studies have multiple domains of unclear or high risk of bias; downgraded by 1 level for study limitations. 6There are no data regarding the primary outcome measure for 14 participants in the intervention group and 12 participants in the control group at 12 weeks. Dropout is not explained. Almost all of the bias domains are rated as either unclear or high risk; downgraded by 1 level for study limitations. 7Zero events in either group; downgraded by 1 level for imprecision.