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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