Piracetam for dementia or cognitive impairment.

OBJECTIVES

To determine the clinical efficacy of piracetam for the features of dementia or cognitive impairment, classified according to the major subtypes of dementia: vascular, Alzheimer's disease or mixed vascular and Alzheimer's disease or unclassified dementia or cognitive impairment not fulfilling the criteria for dementia.

SEARCH STRATEGY

The Cochrane Dementia and Cognitive Impairment Group Register of Clinical Trials was searched using the terms "piracetam", "nootropic" and "2-oxo-l-pyrrolidine acetamide". Electronic bibliographic databases including Medline, Embase, PychLit, Current Contents, Sociofile were searched back to 1966 with the terms piracetam, nootropics, 2-oxo-1-pyrrolidine and trials. In addition the pharmaceutical company responsible for marketing most of the piracetam worldwide, UCB Pharma, provided a comprehensive list of abstracts, which included many unpublished studies. As many of these unpublished, placebo control studies will be reviewed as possible.

SELECTION CRITERIA

All unconfounded trials specified as randomised in which treatment with piracetam was administered for more than a day and compared with placebo in patients with dementia of the Alzheimer's type, vascular dementia or mixed vascular and Alzheimer's disease or uncalssified dementia or cognitive impairment not fulfilling the criteria for dementia.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers. Each study was independently verified as fulfilling the inclusion criteria. Studies were rated for methodological quality by assessment of blinding and loss before analysis as described by Jadad et al. (1996). Studies were pooled if appropriate and possible, and the pooled odds ratios (95%CI) or the average differences (95%CI) were estimated. Where possible, intention-to-treat data were used. Sensitivity analyses were performed to determine if successive elimination of those studies performing most poorly on these quality criteria changed the effect estimate.

MAIN RESULTS

Unfortunately, many of these studies were crossover in design and data were unavailable from the first period. In many other studies data were not able to be extracted from the first period. From the data that were pooled there was only one outcome where significant amounts of evidence were available, Global Impression of Change. There was evidence of heterogeneity in the results from the individual studies, Chi squared test = 20.8 (df=5). Using a fixed effects model the odds ratio for improvement in the Piracetem group compared with the Placebo group was 3.55, [95% CI][2.45, 5.16]. If a random effects model was used the odds ratio was 3.47 [1.29, 9.30]. If one single-blind study was excluded, the fixed effects model yielded an odds ratio of 3.36 [2.29, 4.99] and if a random effects model was applied then the odds ratio was 2.89 [1.01, 8.24]. The evidence of effects on cognition and other measures, was inconclusive.

REVIEWER'S CONCLUSIONS: At this stage the evidence available from the published literature does not support the use of Piracetem in the treatment of people with dementia or cognitive impairment because effects were found only on global impression of change but not on any of the more specific measures. There is a need for further evaluation of piracetam by : 1) Obtaining the data from these studies for an individual patient database review, 2) Performing a randomised trial of Piracetam in patients with diagnoses made by currently accepted diagnostic criteria. Piracetam should be trialled for a period of at least 6 months and preferably longer. Specific cognitive instruments which are sensitive to change, Clinician Global Impression of Change, levels of dependency and caregiver quality of life scales should also be incorporated in such a study.