High-Dose Statins: Protecting the Heart, Damaging the Kidneys? Probably Not

An analysis of 2 randomized trials of statin therapy for patients enrolled after an acute coronary syndrome finds that high-dose statins do not increase the risk of kidney injury.

Statin use has been shown to reduce the risk of major cardiac events in patients who experience acute coronary syndrome (ACS). But recent studies have suggested that those taking high doses of popular cholesterol-lowering statins may be more likely to develop acute kidney problems. For example, a study in BMJ published in March 2013 reported that participants taking the highest statin doses were 34% more likely to be hospitalized for acute kidney injury during the first 4 months of treatment than were participants taking lower doses.

Since this and other studies reporting higher kidney risks with high-dose statins were observational, findings from randomized, controlled studies are needed so clinicians can represent benefits and risks accurately to patients. The Journal of the American Heart Association published such a study online on May 1, 2014.

In the study, researchers from Brigham and Women's Hospital in Boston examined the incidence of kidney injury across 2 randomized trials of statin therapy that enrolled patients after an ACS: PROVE IT‐TIMI 22 (N=4162) and A‐to‐Z (N=4497). PROVE IT‐TIMI 22 randomized participants to atorvastatin 80 mg/day or pravastatin 40 mg/day. A‐to‐Z randomized participants to a high‐potency regimen (simvastatin 40 mg/day for 1 month, then simvastatin 80 mg/day) or a delayed moderate‐potency statin strategy (placebo for 4 months, then simvastatin 20 mg/day).

Participants in both studies had serum creatinine assessed serially to monitor for kidney changes. In both trials, patients’ mean serum creatinine levels were similar at baseline and throughout the study period, regardless of the treatment they received. In A‐to‐Z, 11.4% of those receiving the high-potency regimen and 12.4% receiving the delayed moderate‐potency regimen experienced a 1.5‐fold or ≥0.3 mg/dL rise in serum creatinine. In PROVE IT‐TIMI 22, 9.4% of those on atorvastatin 80 mg/day and 10.6% on pravastatin 40 mg/day had elevated creatinine levels. These differences were small and statistically insignificant.

Patients with the highest risk for kidney injury—those with diabetes mellitus or moderate renal dysfunction—were no more likely to have elevated serum creatinine levels than were other participants. All treatment arms had similar rates of adverse events related to kidney injury­.

The previous observational findings—that high-dose statins may cause acute kidney injury—may be explained by residual confounding that can be associated with observational studies. Analysis of the large PROVE IT‐TIMI 22 and A-to-Z studies does not support previous findings. On the contrary, it supports retention of aggressive statin therapy in ACS patients as standard-of-care.

Ms. Wick is a visiting professor at the University of Connecticut School of Pharmacy and a freelance writer from Virginia.