Statins Do Not Appear to Boost Risk of Cognitive Impairment

A systematic review of previous studies finds no evidence of decreased cognitive function associated with statin use.

Although the FDA has issued warnings concerning statins and potential cognitive impairment, a new systematic review of previous studies finds no evidence that statins are related to adverse cognitive effects. The review was published in the November 19, 2013, issue of the Annals of Internal Medicine.

In February 2012, the FDA cautioned that statins may be associated with memory loss or confusion. However, the evidence that led the agency to issue the warning has not yet been published and was primarily based on case reports. Given the large number of patients who use statins and the importance of maintaining cognitive function, the current study reviewed published data to determine whether there is evidence for a relationship between statin use and impaired cognitive function. The review also independently examined whether the FDA post-marketing surveillance database indicates that statins are associated with a higher risk of cognitive adverse events than other medications commonly prescribed for cardiovascular risk or cardiovascular disease.

The researchers searched PubMed, Embase, and the Cochrane Library for cohort studies, cross-sectional studies, case-control studies, and randomized, controlled trials published from inception through October 2012 that assessed cognition in patients receiving statin therapy. A total of 57 studies were selected and assessed for quality.

Low-quality evidence suggested that statin users did not have an increased risk for Alzheimer’s disease and found no reduction in procedural memory, attention, or motor speed among statin users. Data from 2 pooled analyses of cohort studies, a meta-analysis of case-control studies, and 1 cross-sectional study all demonstrated a lower incidence of Alzheimer’s among statin users compared with controls. Among 7 randomized, controlled trials, most showed no difference in attention between patients treated with statins and those receiving placebo. No significant difference was found between statin and placebo patients tested for motor speed in 5 randomized trials and 1 cohort study.

A meta-analysis of 10 cohort studies and a meta-analysis of 2 case-control studies found a decreased risk for dementia associated with statin use, while 1 randomized trial and 1 cross-sectional study found no significant difference in dementia risk between statin and placebo patients. A meta-analysis of 4 cohort studies and 1 case-control study showed a decreased risk for mild cognitive impairment among statin users, while 1 randomized trial and a meta-analysis of 2 cross-sectional studies revealed no difference in risk among statin and placebo patients.

In the separate analysis of FDA databases, data collected from January 1986 to March 2012 indicated a similarly low reporting rate for cognitive-related adverse events in patients receiving statins as for patients receiving other cardiovascular medications.

Although the published evidence does not indicate a relationship between statins and an increased risk for cognitive impairment, the authors note that the strength of the data available is limited by inconsistency, imprecision, and the risk of bias.