Statins to prevent acute kidney injury after cardiac surgery


Statins, is there anything they can’t do? These agents, granted blockbuster status more than 20 years ago, are potent weapons in our fight against cardiovascular disease. But beyond their cholesterol-lowering effects, we’ve seen studies where statins act as anti-inflammatories, improve immune function and even stave off dementia.  Could the wonder-drugs prevent acute kidney injury, a dreaded complication after cardiac surgery, associated with more than a three-fold increase in mortality?

For the video version of this post, click here.

Full disclosure: I research acute kidney injury, or AKI. So welcome to my world, statins – a world where positive clinical trials are as rare as an epidemiologist at a Mr. Personality contest.

The trial, out of Vanderbilt university hospital appeared in JAMA and enrolled 617 individuals undergoing cardiac surgery. The treatment group got 80mg of atorvastatin prior to surgery, and 40mgs a day after that. The placebo group got, well, placebo. As you might imagine, the majority of patients (400) were already taking a statin.  In that case, if you were randomized to placebo, you only got placebo for the day of surgery and the day after. After that, you were back on your home statin dose.

And to boil the results down to a word: nothing. The rate of AKI was 21% in the statin arm and 20% in the placebo arm. Looking at secondary outcomes, there were no differences in rates of death, dialysis, delirium, stroke, or stay in the ICU.

This might be expected in the group that was already on statins – after all, skipping two days of the drug might not be enough to make a real difference. But if we look at the statin-naïve group, the rate of AKI was 22% in the statin group and 13% in the placebo group. This was not statistically significant but the trend here is clearly in the wrong direction. In fact, if we look at absolute creatinine change –where higher levels are worse- those on the statin had a small, but statistically significant increase in creatinine compared to those on placebo.

But take these numbers with a grain of salt. The data safety and monitoring board forced the study authors to stop recruitment of statin-naïve patients about 2/3rds of the way through the study. They did this because they saw a signal of harm from statins in that group. So the fact that we see harm may be biased by the DSMBs choice to stop that part of the study early.

Now, would I have stopped the study if I were on the DSMB?  Probably. The odds that continuing to recruit would show a benefit of statin were really low, and you don’t want to expose patients to potential harm. But despite that, we can’t accept the results of an early-termination arm of a trial with the same gusto that we would had the trial continued to completion.  In short, the jury is still out as to whether statin use is actually harmful in terms of AKI. But I can say for now I’m pretty convinced it ain’t helping anybody.