Statins and cognitive function: a systematic review

Abstract

Background: Despite the U.S. Food and Drug Administration (FDA) warning regarding cognitive impairment, the relationship between statins and cognition remains unknown.

Purpose: To examine the effect of statins on cognition.

Data sources: PubMed, Embase, and Cochrane Library from inception through October 2012; FDA databases from January 1986 through March 2012.

Study selection: Randomized, controlled trials (RCTs) and cohort, case-control, and cross-sectional studies evaluating cognition in patients receiving statins.

Data extraction: Two reviewers extracted data, 1 reviewer assessed study risk of bias, and 1 reviewer checked all assessments.

Data synthesis: Among statin users, low-quality evidence suggested no increased incidence of Alzheimer disease and no difference in cognitive performance related to procedural memory, attention, or motor speed. Moderate-quality evidence suggested no increased incidence of dementia or mild cognitive impairment or any change in cognitive performance related to global cognitive performance scores, executive function, declarative memory, processing speed, or visuoperception. Examination of the FDA postmarketing surveillance databases revealed a low reporting rate for cognitive-related adverse events with statins that was similar to the rates seen with other commonly prescribed cardiovascular medications.

Limitations: The absence of many well-powered RCTs for most outcomes resulted in final strengths of evidence that were low or moderate. Imprecision, inconsistency, and risk of bias also limited the strength of findings.

Conclusion: Larger and better-designed studies are needed to draw unequivocal conclusions about the effect of statins on cognition. Published data do not suggest an adverse effect of statins on cognition; however, the strength of available evidence is limited, particularly with regard to high-dose statins.