Statins in perioperative prevention of acute kidney injury in patients undergoing cardiac surgery: reply

We appreciate the constructive comments by Dr Kandula with regard to our meta-analysis and the potential renoprotective role of statins in patients undergoing cardiac surgery.1 As correctly stated by the author, only a few studies (n = 5) reported data on the endpoint renal failure with variable definitions, including need for postoperative dialysis or elevated creatinine levels (>2.0 mg/dL). A clear distinction between the impact of statins on acute kidney injury and the need for dialysis after cardiac surgery was impossible in retrospect and after detailed evaluation of included studies. Therefore, the primary authors' definitions were accepted for meta-analysis purposes. As stated in our study, this resulted in significant heterogeneity among studies (I2 = 58.3%; P = 0.05) with unknown impact on the reported estimated statin treatment effect for the endpoint renal failure (OR 0.78; 95% CI 0.46–1.31; P = ns). Of note, the only study investigating the effects of statins on new-onset renal failure in 1282 patients undergoing myocardial revascularization by Tabata et al.2 revealed a 61% reduction in the odds for renal failure in propensity-matched cohorts (OR 0.39; 95% CI 0.18–0.82; P = 0.01), but was restricted by its' retrospective design. In view of the limited clarity of available data, we fully support Dr Kandula's demand for future trials investigating the potential renoprotective role of statins in cardiac surgery.