November 18th, 2013
No Evidence That Statins Impact Cognitive Function
Larry Husten, PHD
In 2012 the FDA revised the label of statins to include a warning about reports that the drugs had been linked to memory loss or confusion. The FDA action appeared to be based largely on case reports. Despite concerns about this topic that have appeared sporadically in recent years, no high-quality review of the topic has appeared until now. In a paper published in Annals of Internal Medicine, Karl Richardson and colleagues report on a systematic review of the literature to assess the effect of statins on cognitive function.
The authors reviewed 25 trials, including randomized, controlled trials and cohort, case-control, and cross-sectional studies, that evaluated cognition in patients taking statins.
Their review found little evidence to support any adverse effect on cognitive function:
“… low-quality evidence suggested no increased incidence of Alzheimer disease and no difference in cognitive performance in procedural memory, attention, or motor speed. Moderate-quality evidence suggested no increased incidence of dementia or mild cognitive impairment, nor any change in cognitive performance related to global cognitive performance scores, executive function, declarative memory, processing speed, or visuoperception.”
In a second analysis of the FDA post-marketing surveillance databases, the investigators found similar reporting rates for cognitive-related adverse events for statins and two other widely used drugs, losartan and clopidogrel.
The reviewers noted, however, that much of the data were not high quality and, in particular, there was a sparsity of data for high-dose statins, which are increasingly used.
They concluded that the available evidence does not support concerns linking statin use to cognitive impairment. “Larger and better-designed studies are needed to draw unequivocal conclusions about the effect of statins on cognition.”
2 Responses to “No Evidence That Statins Impact Cognitive Function”
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Very important paper. Thanks for calling attention to this, Larry. We recently reached the same conclusion in a high-quality systematic review:
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;88:1213-21
http://www.ncbi.nlm.nih.gov/pubmed/24095248
While studies, and then reviews of studies, can give a general idea of what is likely to happen, they cannot determine what will happen with any given person. After 25 years of practice in Internal Medicine, I would guess that I have had only about five to seven patients who have stopped their statins due to memory loss or decreased cognitive function. But in every case, they were convinced that their performance improved within a week of stopping and so that the statin was responsible. I would very crudely guess that I have treated at least a few hundred patients with statins. Almost all of those patients who complained of decreased cognitive function started on statins when they were in their 70’s or even 80’s and stopped the drugs when in their late 70’s to 80’s. Since few patients in their 80’s are included in the studies of statins, there is probably inadequate information from studies to make predictions about those patients. The relatively short duration of the studies compared to the decades of actual use likely also limits detection. If the statins are causing the cognitive dysfunction my patients believe they are causing, is it missed in younger people because only older people are susceptible? or does it just not show up because the interference is mild enough that it will only be noticed where cognition is otherwise compromised, as from aging?