A randomized placebo-controlled trial of Ginkgo biloba for the prevention of cognitive decline.
OBJECTIVE
To assess the feasibility, safety, and efficacy of Ginkgo biloba extract (GBE) on delaying the progression to cognitive impairment in normal elderly aged 85 and older.


METHODS
Randomized, placebo-controlled, double-blind, 42-month pilot study with 118 cognitively intact subjects randomized to standardized GBE or placebo. Kaplan-Meier estimation, Cox proportional hazard, and random-effects models were used to compare the risk of progression from Clinical Dementia Rating (CDR) = 0 to CDR = 0.5 and decline in episodic memory function between GBE and placebo groups.


RESULTS
In the intention-to-treat analysis, there was no reduced risk of progression to CDR = 0.5 (log-rank test, p = 0.06) among the GBE group. There was no less of a decline in memory function among the GBE group (p = 0.05). In the secondary analysis, where we controlled the medication adherence level, the GBE group had a lower risk of progression from CDR = 0 to CDR = 0.5 (HR = 0.33, p = 0.02), and a smaller decline in memory scores (p = 0.04). There were more ischemic strokes and TIAs in the GBE group (p = 0.01).


CONCLUSIONS
In unadjusted analyses, Ginkgo biloba extract (GBE) neither altered the risk of progression from normal to Clinical Dementia Rating (CDR) = 0.5, nor protected against a decline in memory function. Secondary analysis taking into account medication adherence showed a protective effect of GBE on the progression to CDR = 0.5 and memory decline. Results of larger prevention trials taking into account medication adherence may clarify the effectiveness of GBE. More stroke and TIA cases observed among the GBE group requires further study to confirm.
Dodge
H H
HH
Department of Public Health, Oregon State University, Corvallis, OR 97401, USA. Hiroko.Dodge@oregonstate.edu
Zitzelberger
T
T
Oken
B S
BS
Howieson
D
D
Kaye
J
J
D000369:Aged, 80 and over; D001921:Brain / Q000187:drug effects / Q000503:physiopathology; D002543:Cerebral Hemorrhage / Q000139:chemically induced; D003072:Cognition Disorders / Q000503:physiopathology / Q000517:prevention & control*; D015331:Cohort Studies; D003704:Dementia / Q000503:physiopathology / Q000517:prevention & control*; D018450:Disease Progression; D004311:Double-Blind Method; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D046934:Ginkgolides / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000188:drug therapy / Q000503:physiopathology / Q000517:prevention & control; D015233:Models, Statistical; D018696:Neuroprotective Agents / Q000008:administration & dosage; D009483:Neuropsychological Tests; D018697:Nootropic Agents / Q000008:administration & dosage / Q000009:adverse effects; D010865:Pilot Projects; D010919:Placebos; D040242:Risk Reduction Behavior; D016896:Treatment Outcome
D004365:Drugs, Chinese Herbal; D046934:Ginkgolides; D018696:Neuroprotective Agents; D018697:Nootropic Agents; D010919:Placebos