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.”