This condition (“an acute change in mental status that is worrisome to patients and families”) is a big concern for many elderly patients (and their families) having major surgery. Unfortunately we don’t yet know enough about the predisposing factors and direct causes to do very much about preventing postoperative delirium, apart from avoiding some things which are obviously bad for all patients (e.g. low blood pressure, inadequate oxygen, etc). Delirium increases the average length of a hospital stay by about a week, is associated with a variety of complications and increased costs, and may even be linked to permanent brain deficits.
This study suggests that statin drugs predispose to postoperative delirium. Is the conclusion correct? Should it change medical practice, which currently strongly favors the continuation of statins after surgery because of their protective effect on the heart?
The Canadian study uses epidemiologic methods to look back at a large number (over 500,00) of hospitalised patients, and, using sophisticated analytical and statistical tools, concludes that statins taken before surgery increase delirium by about 30%. The authors suggest that one of the effects of statins, which influence the control of very small blood vessels and their supply of blood to brain tissue, may lead to ischemia (inadequate oxygen) for parts of the brain, and hence delirium.
In my view, and the view of the commentator, the findings are worrisome, but the study design isn’t strong enough to influence medical practice just yet. For example, the number of patients the study found with delirium is less than a tenth of the likely true number and these patient may differ in some systematic way from the norm.
The findings are strong enough that it is now important for us to study this issue in a better way. That means a randomised, controlled clinical trial in which statins are stopped in some patients, continued in other (control) patients, and delirium is diagnosed in a through way.
What you can do
Stay on your statins if you are to have surgery.
Always check with your doctors on what medications you need to continue, or stop, before anesthesia and surgery.
An excellent summary of postoperative delirium (for a medical reader) is found on the ASA website here.