Table 1

Systematic reviews of clinical trials of ginkgo biloba extracts

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


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

Linde et al. BMC Complementary and Alternative Medicine 2001 1:5   doi:10.1186/1472-6882-1-5

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