Cochrane for Clinicians
Putting Evidence into Practice
The Effect of Statins on Dementia and Cognitive Decline
Am Fam Physician. 2017 Feb 1;95(3):151-152.
Author disclosure: No relevant financial affiliations.
Do statins prevent dementia or cognitive decline?
Statins given in later life to patients at risk of vascular disease do not prevent dementia or cognitive decline compared with placebo. Adverse effects are similar between groups.1 (Strength of Recommendation: A, based on consistent, good-quality patient-oriented evidence.)
In 2015, the prevalence of dementia in the U.S. population older than 65 years was approximately 11%. The estimated worldwide cost of dementia will reach $1 trillion by 2018; thus, prevention strategies are critical.2 There is a close association between dementia and cardiovascular disease, and because statins have secondary preventive effects for cardiovascular disease,3 it has been posited that they may also help prevent dementia. Several observational studies have reported a slight benefit for statin use in the prevention of dementia.4–6 This Cochrane review addressed whether statins are effective for the primary prevention of dementia or cognitive decline.1
The authors of this review examined two randomized controlled trials with 26,340 participants 40 to 82 years of age, including 11,610 persons 70 years or older.1 One trial compared simvastatin (Zocor) with placebo over five years; the other compared pravastatin (Pravachol) with placebo over 3.2 years. All of the participants in both study populations had a moderate to high vascular risk. The cognitive assessments used in these two studies were heterogeneous and had different end points, including changes in performance on the Mini-Mental State Examination (which is copyright restricted and requires a fee for the form and administering the test), the Stroop Color and Word Test, and the Picture-Word Learning test, among others.
There were no differences in the number of patients who developed dementia or cognitive decline between those taking statins or placebo. Although both studies evaluated cognitive decline, only the simvastatin study examined the incidence of dementia. Among the 20,536 participants in the simvastatin study who were randomized to treatment or placebo, 31 new cases of dementia developed in each arm of the study. Both studies were at low risk of bias, and there were no differences in the number of adverse effects leading to discontinuation.
An analysis from the Agency for Health-care Research and Quality cites the availability of only low-quality, discordant evidence to link statin use and prevention of cognitive decline.7 In its most recent clinical guideline, the American Academy of Neurology does not address statin use to prevent dementia.8
The practice recommendations in this activity are available at http://www.cochrane.org.
The opinions and assertions herein are those of the authors, and should not be construed as official or as those of the Department of the Air Force, the Department of the Navy, the Uniformed Services University of the Health Sciences, or the Department of Defense.
REFERENCESshow all references
1. McGuinness B, Craig D, Bullock R, Passmore P. Statins for the prevention of dementia. Cochrane Database Syst Rev. 2016;(1):CD003160....
2. Hebert LE, Weuve J, Scherr PA, Evans DA. Alzheimer disease in the United States (2010–2050) estimated using the 2010 census. Neurology. 2013;80(19):1778–1783.
3. Stone NJ, Robinson JG, Lichtenstein AH, et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines [published corrections appear in J Am Coll Cardiol. 2015;66(24):2812, and J Am Coll Cardiol. 2014; 63(25 pt B):3024–3025]. J Am Coll Cardiol. 2014;63(25 pt B):2889–2934.
4. Wong WB, Lin VW, Boudreau D, Devine EB. Statins in the prevention of dementia and Alzheimer's disease: a meta-analysis of observational studies and an assessment of confounding. Pharmacoepidemiol Drug Saf. 2013;22(4):345–358.
5. Swiger KJ, Manalac RJ, Blumenthal RS, Blaha MJ, Martin SS. Statins and cognition: a systematic review and meta-analysis of short- and long-term cognitive effects. Mayo Clin Proc. 2013;88(11):1213–1221.
6. Song Y, Nie H, Xu Y, Zhang L, Wu Y. Association of statin use with risk of dementia: a meta-analysis of prospective cohort studies. Geriatr Gerontol Int. 2013;13(4):817–824.
7. Williams JW, Plassman BL, Burke J, Benjamin S. Preventing Alzheimer's disease and cognitive decline. Evid Rep Technol Assess (Full Rep). 2010;193:1–727.
8. Doody RS, Stevens JC, Beck C, et al. Practice parameter: management of dementia (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2001;56(9):1154–1166.
These are summaries of reviews from the Cochrane Library.
This series is coordinated by Corey D. Fogleman, MD, Assistant Medical Editor.
A collection of Cochrane for Clinicians published in AFP is available at https://www.aafp.org/afp/cochrane.
Copyright © 2017 by the American Academy of Family Physicians.
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