A wide-ranging and systematic review of more than two dozen trials of statin drugs has found no link to cognitive problems, prompting researchers to call on the U.S. Food and Drug Administration to no longer require such warnings on statin packaging.
It is the latest blow in a running debate over the cognitive impact of such drugs — and may prove definitive.
Statins, or HMG-CoA reductase inhibitors, are widely used to reduce high cholesterol levels. Their packaging has been required since 2012 to warn that the drugs could cause cognitive changes including attention span, problem solving, memory, and language, or visuospatial abilities.
Although the decision by the FDA to give such warnings was based on a range of surveillance and case reports, observational studies, and randomized trials, later findings have cast doubt on its validity. So Brian Ott, M.D., of The Alzheimer’s Disease & Memory Disorders Center at Rhode Island Hospital, Providence, Rhode Island, and his team looked at 25 randomized clinical trials including 46,836 patients. In addition, they carried out a meta-analysis, statistically combining the results of 14 of the studies.
This showed “no significant effect of statin use on the mental capacity of either people with normal brain functioning or those with Alzheimers’ disease.” In light of this result, the researchers call for the statin warning to be reconsidered.
Ott adds that the differences in the results from this review and previous studies should be investigated. He suggests that statin overdoses may have caused some instances of mental changes, rather than the drugs posing a danger at normal levels.
His review appears in the Journal of General Internal Medicine. The authors write, “We found no significant effects of statin treatment on cognition. Given these results, it is questionable whether the FDA class warning about potential cognitive adverse effects of statins is still warranted.”
Ott believes that the heart benefits of statin therapy outweigh the possible cognition problems.
“We hope that as a result fewer people will be taken off their statin drugs unnecessarily and that a physician, when faced with a patient who is concerned about being confused when they’re on a statin should think about whether there might be some other explanation,” he said.
“Perhaps they’re taking too much of the drug, or there may be some entirely different problem causing their mental confusion such as a medical condition or sub-toxic effects of some other drug.
“It’ll make physicians and patients families think more about what else may be causing the problem other than the statin drug they’re taking.”
Ott has disclosed commercial interests with Lilly, Pfizer, Roche and other pharmaceutical companies.
These new results are in line with a safety statement from the American College of Cardiology and the American Heart Association in 2013 advising patients taking statins to be evaluated for causes other than their cholesterol medication if they seem to be confused or have memory problems.
Commenting on the study in the same journal, Huseyin Naci, Ph.D., of the London School of Economics and Political Science, U.K., said, “This is the most comprehensive review to date evaluating the causal relationship between statin use and cognitive impairment. The authors did a commendable job in compiling a comprehensive list of relevant randomized controlled trials, performing extensive statistical analyses, and interpreting their findings with careful clinical insight.
“The authors’ laudably cautious interpretation of their findings confirms that existing randomized controlled trial evidence does not support the FDA warning about potential adverse effects of statins on cognition. This is an important, timely, and clinically meaningful finding: Clinicians, patients, and their caregivers can take comfort in knowing that there does not appear to be a causal relationship between statin use and cognitive impairment.”
Naci added that the study questions the validity of the Adverse Events Reporting System, which regularly contradicts the results of randomized trials. The system may also have unintended consequences, he said. For example, the FDA’s safety warnings about antidepressants were shown in a study to significantly decrease antidepressant use, “well beyond levels that the regulators had intended.”
“It is possible that individuals stopped taking statins or took smaller doses as an unintended result of the widespread media coverage that publicized the FDA’s decision,” he writes in the Journal of General Internal Medicine.
“Regulatory decisions on medications should be based on current best evidence: up-to-date information from relevant, valid research. Although previous reviews on this topic called for additional larger, better designed studies, Ott and colleagues settle the question about the cognitive harms of statins,” he concluded.
Ott, B.R. et al. Do Statins Impair Cognition? A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Journal of General Internal Medicine, 10 January 2015 doi: 10.1007/s11606-014-3115-3
Naci, H. Capsule Commentary on Ott et al., Do Statins Impair Cognition? A Systematic Review and Meta-analysis of Randomized Controlled Trials. Journal of General Internal Medicine, 27 January 2015, doi: 10.1007/s11606-014-3158-5