A Cochrane review [Abstract] 1 included 4 studies with a total of 1154 patients with Alzheimer's disease (AD). Age range was between 50 and 90 years. All participants had a diagnosis of probable or possible AD according to standard criteria and most participants were established on a cholinesterase inhibitor. Statins (atorvastatin 80 mg or simvastatin 20 or 40-80 mg daily) were compared with placebo, follow-up times ranged between 22 and 18 months. In all trials, serum low density lipoprotein (LDL) cholesterol was reduced by 37-54%. Statins did not provide any beneficial effect for the primary outcome, change in Alzheimer's Disease Assessment Scale- cognitive subscale (ADAS-Cog) from baseline, (mean difference -0.26, 95% CI -1.05 to 0.52; 4 studies, n=1110). When the data were pooled there was no significant benefit from statins for Mini Mental State Examination (MMSE): (mean difference from baseline --0.32, 95% CI -0.71 to 0.06). There was no significant difference between statins and placebo as regards treatment related adverse effects (3 studies). There was no significant difference in global function, behaviour or activities of daily living in the statin and placebo groups. There were no studies identified assessing the role of statins in treatment of vascular dementia. There was no evidence that statins were detrimental to cognition.
Comment: The quality of the evidence is downgraded by indirectness (short follow-up time).
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