Dose-dependent effect of statins on the incidence of acute kidney injury after cardiac surgery.
BACKGROUND
Acute kidney injury (AKI) after cardiac surgery is associated with increased morbidity and mortality.


METHODS
We assessed whether statin treatment is associated with a lower incidence of postoperative AKI in 2,104 consecutive patients who underwent coronary artery bypass graft or valve surgery at the Minneapolis Veterans Administration Medical Center. Acute kidney injury was defined as absolute increase greater than 0.3 mg/dL or relative increase greater than 50% in serum creatinine from baseline, within 48 hours after surgery or requiring postoperative hemodialysis per AKI network. Propensity scores were utilized to adjust for the differences between the statin and the no-statin treatment groups. All statins were converted to equivalent-dose simvastatin and divided at the median to construct high-dose (≥40 mg) and low-dose (<40 mg) statin groups.


RESULTS
Of the 2,104 patients, 1,435 (68%) were taking statins (638 high-dose) and 495 (24%) developed AKI (25% high-dose vs 40% low-dose vs 35% no-statin; p = 0.014). Estimated preoperative glomerular filtration rate (p = 0.003), diabetes mellitus (p=0.02), valve surgery with or without coronary artery bypass graft (p = 0.024), cardiopulmonary bypass time (p = 0.001), and intraaortic balloon pump (p = 0.055) were independent predictors of AKI. After propensity adjustment statin treatment was not associated with postoperative AKI (odds ratio 0.79; 95% confidence interval 0.59 to 1.06; p = 0.11 for high-dose v. no-statin). After full adjustment for all independent predictors of AKI, the results did not change. Statins also had no effect on the incidence of postoperative hemodialysis (0.8% high-dose vs 1.9% low-dose vs 1% no-statin; p = 0.15).


CONCLUSIONS
Statin treatment is not associated with a lower incidence of AKI after cardiac surgery.
Department of Internal Medicine, Veterans Administration Medical Center, Minneapolis, Minnesota 55417, USA.
Salima
S
Mithani
Michael
M
Kuskowski
Yelena
Y
Slinin
Areef
A
Ishani
Edward
E
McFalls
Selcuk
S
Adabag
D058186:Acute Kidney Injury / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control*; D000368:Aged; D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000706:statistics & numerical data*; D015331:Cohort Studies; D015897:Comorbidity; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data; D003327:Coronary Disease / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000453:epidemiology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006331:Heart Diseases / Q000453:epidemiology / Q000601:surgery; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000008:administration & dosage*; D015994:Incidence; D008297:Male; D011182:Postoperative Care; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control*; D011292:Premedication; D006435:Renal Dialysis / Q000706:statistics & numerical data; D019821:Simvastatin / Q000008:administration & dosage; D015996:Survival Rate
D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D019821:Simvastatin