Elderly people who take cholesterol-lowering statins may be at higher risk for delirium after surgery, say Canadian researchers who suggest temporarily stopping use of the drugs before surgery to prevent the complication.

People over 70 commonly show delirium or confusion after elective surgery, such as to repair hip fractures. Doctors now recognize delirium as a complication that should be prevented, recognized and treated.

Delirium not only causes anxiety for patients and their families, it also contributes to longer hospital stays, prolongs the need for intensive care and may disrupt or delay care, the researchers said.

In Tuesday's issue of the Canadian Medical Association Journal, Dr. Donald Redelmeier of Ontario's Institute for Clinical Evaluative Sciences and his colleagues concluded the use of statins is associated with a 28 per cent increased risk of delirium in elderly patients who had surgery between 1992 and 2002.

To come to that conclusion, the researchers reviewed hospital and outpatient pharmacy records of more than 280,000 patients aged 65 or older who were admitted for elective surgery.

Among the seven per cent of patients taking statins, 3,195 experienced delirium after surgery, the researchers said.

The rate was significantly higher among patients taking statins at 14 per 1,000 than among those not taking the medications, 11 per 1,000. The findings translate into 1.3 times higher odds for the statin group, the researchers reported.

"Our results suggest that this association was more than a coincidence, particularly among patients who received higher doses of statins and had longer duration noncardiac surgeries," the study's authors wrote.

Dissenting view

The link between statins and risk of delirium was not seen for other cholesterol-lowering medications, heart disease medications or other common drugs, the researchers said.

"Until more data are available, a recommendation to temporarily interrupt the use of statins before surgery may be a reasonable compromise," the study concluded.

If needed, restarting statins after surgery could protect the heart without the risk of delirium, the researchers added.

"Unlike the authors, I believe it is premature to recommend stopping the use of statins in elderly surgical patients. The methodology used in this study is simply too limited to compel practice change," Dr. Edward Marcantonio of Harvard Medical School in Boston said in a commentary accompanying the study.

No one knows how stopping statins could affect other aspects of a patient's health after surgery. And in the increasingly fragmented nature of the health-care system where seniors see many doctors prescribing various medications, there is a risk that statins would not be restarted after surgery, Marcantonio added.

But given the aging population, prevalence of delirium and its costs, he agreed with the researchers that even a modest reduction in risk would translate into substantial benefit for patients and the health-care system.