Should all patients with chronic kidney disease take a statin?
Cardioprotective effects in stages 1–4
Since patients with chronic kidney disease were excluded from most of the major statin trials, the best evidence in those with non-dialysis-dependent disease comes from post hoc analysis of data from the CARE study.14 While this trial excluded patients with more than 2+ proteinuria on dipstick analysis and those with creatinine values greater than 1.5 times the upper limit of normal, 1,711 of the initial 4,159 patients had a creatinine clearance of less than 75 mL/min; the mean creatinine clearance in this subgroup was 61. In this subgroup, pravastatin therapy was associated with a significantly lower risk of cardiovascular death or recurrent nonfatal myocardial infarction (MI) (hazard ratio 0.72, P < 0.05).
Similarly, in the 4,491 patients with chronic kidney disease (mean GFR 55 mL/min/1.73 m2) in the Pravastatin Pooling Project, the hazard of new MI, cardiovascular death, or cardiac intervention was nearly 25% lower in the pravastatin group.15
The ongoing Study of Heart and Renal Protection (SHARP),16 a randomized trial of ezetimibe/simvastatin (Vytorin) that enrolled 6,000 people with stages 3 to 4 kidney disease and 3,000 dialysis patients, will help in determining whether statin therapy prevents new vascular events. The study was launched in 2003 and has now completed enrollment. The primary outcome measure will be the time to first vascular event; secondary analyses will address whether statins decrease proteinuria or slow the progression of kidney disease.
Cardioprotective effects in dialysis patients
The only major randomized trial of statins ever conducted in dialysis patients with diabetes, the German Diabetes and Dialysis Study (4D), did not find atorvastatin 20 mg to have any benefit compared with placebo in reducing a composite end point of death from cardiac causes, stroke, and nonfatal MI over a median of 4 years of follow-up, despite a decrease in LDL-C of over 40% in the treatment group.17 Adverse events were similar in the two groups. The lack of a detectable benefit may be due to differences in the cardiovascular milieu in dialysis patients, who may have more advanced disease, with preexisting cardiac remodeling and congestive heart failure, which may not be modified to the same extent by statin therapy. Alternatively, the dose of atorvastatin may have been too low, or 4 years of treatment may not be sufficient to detect a benefit in these patients.
An ongoing prospective, randomized, placebo-controlled trial in 3,000 hemodialysis patients, called A Study to Evaluate the Use of Rosuvastatin in Subjects on Regular Haemodialysis: an Assessment of Survival and Cardiovascular Events (AURORA),18 will help to clarify the role of statins in this population.
CONCLUSION
The National Kidney Foundation guidelines1,19 note that people with chronic kidney disease are at high risk of cardiovascular disease and therefore should be treated according to guidelines for treating traditional risk factors in high-risk groups. We believe that those with dyslipidemia who are in stages 1 through 4, particularly those with other risk factors for coronary heart disease, should receive a statin, with an LDL-C target of less than 100 mg/dL, even though we have few data from large trials focused on this population and even though LDL-C may not be the only reason to consider statin use. The pleiotropic effects of statins on proteinuria and progression of kidney function loss may be of benefit in this population as well, although we would not recommend starting a statin solely for these effects until more data are available.
Despite the negative results of the 4D trial, given the relative safety of statins and the lack of any trial data suggesting harm in patients with chronic kidney disease, in our practice we treat dialysis patients with known cardiovascular disease with a statin, with a target LDL-C level less than 100 mg/dL. In dialysis patients without known cardiovascular disease, the use of a statin is even more controversial, and decisions should be made on an individual basis.
Results from the SHARP, AURORA, and PLANET trials, each of which is focused on patients with chronic kidney disease, will help determine whether statins benefit patients at this stage of disease.
