All about Lipitor

Are statins efficient in treatment of dementia?

A number of studies have connected elevated cholesterol levels in the blood and Alzheimer's disease, however most recent studies say that even if the patient uses the best cholesterol-lowering medications like Lipitor it will not help in treatment of the disease.

Such drugs as Lipitor lower cholesterol by inhibiting an enzyme which is responsible for the production of the substance in the human organism. The drug thus reduces the amount of low-density lipoproteins which are considered to be bad for health.

Studies which have shown that elevated cholesterol may have caused Alzeheimer's disease made scientists wonder if preparations like Lipitor would be effective in decreasing the risk of disease development and dementia which is caused by the disorder. In animal studies the decreased levels of cholesterol significantly affected the expression of Alzheimer's disease, thus a conclusion was made that such approach might also be effective in humans.

The new review appears in the latest issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews like this one draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic. "From these trials, which contained very large numbers and were the gold standard ... it appears that statins given in late life to individuals at risk of vascular disease do not prevent against dementia," said lead study author Bernadette McGuinness, a senior clinical research fellow in geriatric medicine at Queen's University in Belfast, Ireland. "I feel the follow-up time was sufficient to allow for an effect to appear," she added.

The review, an update to an earlier review completed in 2001, comprised 26,340 participants in two major studies. One study, the Medical Research Council/British Heart Foundation Heart Protection Study (HPS), looked at simvastatin (Zocor) use in 20,536 patients and followed them for five years. The other study, the PROSPER trial, looked at pravastatin use in 5,804 patients, with an average follow-up of 3.2 years.

Both studies were double-blind randomized, placebo-controlled studies of statin medications in individuals at risk for dementia and Alzheimer disease. Taken together, the studies comprised adults between the ages of 40 and 82.

Although the review had not shown any evidence that the statin treatment was harmful to cognition, the author was also unable to find any difference between patients receiving placebo and Lipitor when it came to incidents of dementia.

"Statins have a range of mechanisms that could help or hurt cognition," said Beatrice Golomb, M.D., of the department of family and preventive medicine at the University of California, San Diego. "Regarding statins as preventive medicines, there are a number of individual cases in case reports and case series where cognition is clearly and reproducibly adversely affected by statins."

Golomb also said that some randomized trials have shown that the net effect of statin medications was significantly adverse and others that have shown it was neutral, but that none has shown statin use to be favorable for cognition. McGuinness said that while the two large trials showed that statins given later in life do not protect against dementia, "it is unclear, however, if statins given in middle age for many years can protect against dementia in later life, as the studies did not address this."

She noted that neither study aimed to assess the prevention of dementia primarily; in fact, dementia was at most a secondary outcome in the studies. As a result, "some people with dementia may not have been picked up by the screening, especially in HPS, but it is difficult to know."

Patients taking statins such as Lipitor might not take them reliably if they've developed cognitive problems or side effects, Golomb said. "That is, the very patients who develop cognitive problems or adverse effects as a result of statins will be less compliant on statins, the literature says, and then may be selectively excluded from the study." As a result, the study could portray unrepresentatively favorable results where cognitive function is concerned, she said. "However, the conclusion, an important one, remains largely correct."