ESC 2013 Report – Statins may protect against dementia and cataracts

Statins might help prevent dementia and cataracts, according to two studies.

In a retrospective analysis of 57,669 Taiwanese patients who were over 65, those in the highest daily dosage tertile had a 59% reduced risk of new-onset dementia compared with controls, according to Cho Kai Wu, MD, of the National Taiwan University Hospital in Taipei, and colleagues.

The protective benefit was smaller but still evident in the lowest and middle daily dosage tertiles — 38% and 31% reduced risk, respectively (P<0.001 for trend), they reported at the annual meeting of the European Society of Cardiology.

In a second study, John B. Kostis, MD, from the UMDNJ-Robert Wood Johnson Medical School in New Brunswick, N.J., and colleagues found that the risk of cataract was reduced by 20% among statin users versus non-statin users.

The absolute risk reduction was 1.4%, which equates to 71 persons needed to treat with statins to prevent one cataract, Kostis said at a press conference.

For the dementia study, Wu and colleagues used a random sample of 1 million patients covered by Taiwan’s National Health Insurance program. From this they identified 57,669 patients 65 years or older who had no history of dementia in 1997 and 1998. The mean follow-up was 4.5 years.

A total of 42,461 patients had not taken statins and served as controls; another 15,200 patients had taken statins. From both cohorts, researchers found 5,516 cases of new dementia.

In addition to looking at daily dosage outcomes, patients also were divided into tertiles according to their total equivalent dosage — across the entire follow-up period, which averaged 4.5 years.

Those in the highest tertile of total equivalent dosage had a 67% reduced risk of new-onset dementia compared with controls. Again, the protective benefit was still there for those in the lowest and middle tertiles, albeit smaller — 23% and 37%, respectively (P<0.001 for trend).

The protective effect of statins remained in different age, gender, and cardiovascular risk subgroups, Wu reported at a press conference.

The investigators did not distinguish between different types of dementia, but Wu suggested the beneficial effect was most likely driven by a reduction in vascular dementia — one of the most common causes of dementia along with Alzheimer’s disease.

“A disorder of cholesterol metabolism could lead to increased incidence of cerebral vascular disease, and elevated levels of cholesterol may result in a high inflammatory state that is associated with neurodegeneration,” Wu said.

Sidney C. Smith Jr., MD, director of the Center for Cardiovascular Science and Medicine at the University of North Carolina School of Medicine in Chapel Hill, said that the Chinese people in general have an increased risk of stroke compared with other populations.

Wu noted the warning in February 2012 by the FDA that stipulated all statins must warn of the potential for statin-induced cognitive changes, especially for the older population.

He said that previous studies had considered statin therapy to exert a beneficial effect on dementia, but few large-scale studies have focused on the impact of statins on new-onset dementia in the geriatric population.

The researchers also said the potency of the statins, rather than their solubility, was a major determinant in reducing dementia. They pointed out that high-potency statins such as atorvastatin and rosuvastatin showed a significant inverse association with developing dementia in a dose-response manner.

In the cataract study, the greatest benefit was seen when treatment was initiated in younger patients. The risk was cut in half for patients in their 40s, for example, compared with only a 10% reduced risk for patients in their 70s.

“It is possible that the two processes — aging and statins — work in parallel or interactively,” Kostis said.

Researchers also found that duration of statin therapy influenced the protective benefit on cataracts. Those on statins for 14 years, for example, had a 55% reduced risk, while those on statins for 6 months only had a 10% reduced risk.

Their meta-analysis included 13 clinical trials comprising 2.4 million patients and 25,618 cataracts. The average duration of statin treatment was 54 months, the average age was 61, and nearly 60% were men.

The results were confirmed by several sensitivity analyses, Kostis pointed out.

“Our findings dispel worries about the safety of statins when it comes to cataracts and lend additional support to long-term statin use,” he concluded.

Kostis said the meta-analysis is limited because of different study designs, some studies without cataract as a predefined endpoint, potential incomplete adjustment for confounders, and possible reporting and publication bias.

Wu and colleagues noted their study limitations included the retrospective design, the potential for other confounders, and the potential for lost data that could have impacted the results.

The researchers for both studies had no conflicts of interest to declare.

Reference:

Wu C, et al “Statin use and the incidence of dementia in the elderly: a nationwide data survey” ESC 2013.

Reference:

Kostis JB, et al “Statins prevent cataracts: A meta-analysis” ESC 2013; Abstract 80970