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Table 1 Systematic reviews of clinical trials of ginkgo biloba extracts

From: Systematic reviews of complementary therapies – an annotated bibliography. Part 2: Herbal medicine

      Features   
Author Year Indication Intervention Comparisons Studies 1/2/3/ Results Author's Conclusion
      4/5   
Ginkgo ( Ginkgo biloba )
Pittler 2000 intermittent ginkgo placebo 8 RCT y/y/y/ Increase of pain-free walking Evidence for a modest benefit of
[7] claudication     y/y distance over placebo after 12 uncertain clinical relevance
       or 24 weeks 34 m (95%CI 26–  
       43 m)  
Moher 2000 intermittent ginkgo* placebo 5 RCT y/y/y/ Increase of pain-free walking Inconsistent results from the few
[8] claudication     n/y distance over placebo after 24 available small studies do not
       weeks 32 m (95%CI 14–50 m) allow firm conclusions
Ernst 96 [9] intermittent ginkgo placebo, 10 p/ p/ n/ Most studies low quality. Available evidence promising but
  claudication extract other drugs RCT/CCT n/n Increase of walking distance further high quality research
   EGb761     compared to placebo 24 to 160 needed
       m. At least similar  
       effectiveness compared to  
       other drugs.  
Schneider 92 intermittent ginkgo placebo, 7 RCT/CCT ?/n/n/ mean effect size d = 0.75 Effectiveness over placebo clearly
[10] claudication   other (vs. plac.), 2 y/y (95%CI 0.44–1.07) over shown
    treatment RCT/CCT   placebo  
     (other)    
Letzel 92 intermittent ginkgo ginkgo vs. 5 RCT ?/p/n/ Pooled increase of walking Ginkgo extract EGb761 more
[11] claudication extract plac., ginkgo y/y distance: 45% over placebo for effective than placebo and
   EGb 761 pentoxifyllin 9 RCT   gingko and 57% for similarly effective as pentoxifyllin
    vs. plac. pentoxifyllin   pentoxifyllin  
Kleijnen 91 intermittent ginkgo ginkgo vs. 15 y/y/y/ Many trials low quality. All trials Ginkgo seems effective for
[12] claudication   plac., RCT/CCT n/n with positive results. Evidence intermittent claudication but further
    pentoxifyllin (ginkgo), 5   similar as for pentoxifyllin high quality studies are needed
    vs. placebo RCT/CCT    
     pentoxif.    
Weiss 91 cerebral ins., ginkgo placebo 17RCT/CCT ?/p/p/ 10 of 12 interpretable trials on Effectiveness for both conditions
[13] intermittent extract   (cerebral n/n cerebral insufficieny and all 4 biometrically shown
  claudication EGb761   ins.), 8   interpretable trials on  
     RCT/CCT   intermittent claudication with  
       significant positive results  
Ernst 99 [14] dementia ginkgo placebo 9 RCT y/y/y/ Results collectively suggest Encouraging findings warranting
      y/n that ginkgo is more effective for large scale trials
       dementia than placebo  
Oken 98 [15] Alzheimer ginkgo placebo 4 RCT y/y/n/ Significant effect over placebo Clinical relevance of the observed
  dementia     y/y for cognitive function (Hedges effects has to be confirmed in
       g= 0.41, 95%CI 0.22–0.61) further research
Hopfenmüller cerebral ginkgo placebo 10 RCT, 1 n/ n/ n/ Global response (based on Ginkgo extract superior to placebo
94 [16] insufficiency extract LI   CCT y/y symptom scores): OR 1.98  
   1370     (95%C11.39–2.57) in favour of  
       Ginkgo  
Kleijnen 92 cerebral ginkgo ginkgo vs. 40 RCT/ y/y/y/ Many trials low quality. Virtually Ginkgo seems effective for
[17] insufficiency   plac. CCT n/n all trials reported positive cerebral insufficiency but further
    hydergine (ginkgo), 4   results. Evidence similar as for high quality studies are needed
    vs. plac. RCT/CCT   hydergine  
     (hydergine)    
Ernst 99 [18] tinnitus ginkgo placebo, 5 RCT y/y/y/ 3 trials favour ginkgo over Results suggest that extracts of
    other   y/n placebo, 1 no difference, in one ginkgo biloba are effective in
    treatment (1    trial ginkgo better than another treating tinnitus
    trial)    treatment  
Evans 2000 macular ginkgo placebo 1 RCT y/y/y/ one small trial reporting Insufficient evidence to
[19] degeneration     y/- improvement recommend ginkgo for age-related
        macular degeneration
  1. Features: 1 = comprehensive search, 2 = explicit inclusion criteria, 3 = formal quality assessment, 4 = summary of results for each included study, 5 = meta-analysis; y = yes, p = partly, n = no, - = not applicable, ? = unclear review on all pharmacologic treatments for the respective condition RCT = randomized controlled trials, CCT = non-randomized controlled trials, CS = cohort studies, UCS = uncontrolled studies; OR = odds ratio, RR = rate ratio