Ginkgo biloba does not benefit patients with tinnitus: a randomized placebo-controlled double-blind trial and meta-analysis of randomized trials. Efficacy and tolerability of Ginkgo biloba extract EGb 761 by type of dementia: analyses of a randomised controlled trial.
The objective was to ascertain if Ginkgo biloba benefits patients with tinnitus. The study design was: 1. Randomized double blind trial of Ginkgo biloba versus placebo; 2. A meta-analysis of randomized placebo controlled double blind trials. Participants included 66 adult patients with tinnitus and six (including our study) randomized placebo controlled double blind trials were meta-analysed. The main outcome measures were the Tinnitus Handicap Inventory (THI), Glasgow Health Status Inventory (GHSI) and average of hearing threshold at 0.5, 1, 2, 4 kHz. In the meta-analysis the proportion of patients gaining benefit and an overall odds ratio were determined. The results showed the mean difference in change of the THI, GHSI and hearing between Ginkgo biloba (n = 31) and placebo group (n = 29) was 2.51 (CI -10.1, 5.1, P = 0.51), 0.58 (CI-4.8, 3.6, P = 0.38) and 0.68 db (CI -4.13, 2.8, P = 0.69). Meta-analysis revealed 21.6% of Ginkgo biloba treated patients (n = 107/552) gained benefit versus 18.4% (n = 87/504) of placebo treated patients with an odds ratio of 1.24 (CI 0.89, 1.71). In conclusion, Ginkgo biloba does not benefit patients with tinnitus. Secondary analyses of a randomised controlled trial were performed to find out whether treatment effects of Ginkgo biloba extract EGb 761 differed by type of dementia. Three hundred ninety-five patients aged 50 years or above, with dementia with neuropsychiatric features were treated with EGb 761 (240 mg/day) or placebo for 22 weeks. Patients scored between 9 and 23 on the Short Syndrome Test (SKT), a cross-culturally validated cognitive test battery. Their total score on the Neuropsychiatric Inventory (NPI) was at least 5. Efficacy was assessed by the SKT test battery (primary outcome measure), the Verbal Fluency Test, the Clock-Drawing Test, the NPI, the Hamilton Rating Scale for Depression (HAMD), and the Gottfries-Bråne-Steen Scale (GBS). Applying standard research diagnostic criteria 214 patients were diagnosed with Alzheimer's disease (probable AD or possible AD with cerebrovascular disease) and 181 with probable vascular dementia (VaD). Under EGb 761 treatment the SKT total score improved by -3.0+/-2.3 and -3.4+/-2.3 points in patients with AD and VaD, respectively, whereas the patients on placebo deteriorated by +1.2+/-2.5 and +1.5+/-2.2 points, respectively (p<0.01 for both drug-placebo differences). Significant drug-placebo differences were found for all secondary outcome variables with no major differences between AD and VaD subgroups. The rate of adverse events tended to be higher for the placebo group.