Preoperative statin therapy is associated with lower requirement of renal replacement therapy in patients undergoing cardiac surgery: a meta-analysis of observational studies

Acute kidney injury (AKI) following cardiac surgery is a common complication associated with serious morbidity and mortality. Activation of inflammatory cascade and vascular endothelial dysfunction plays a vital role during the perioperative period leading to AKI. Statins are known to suppress inflammation and improve endothelial dysfunction over and above the cholesterol lowering efficacy. Observational studies with a defined population in terms of preoperative statin therapy and no preoperative statin therapy undergoing cardiac surgery (CABG, isolated valve surgery or both) and with reported data on the incidence of acute renal failure/injury and/or mortality were identified and analysed for inclusion in the analysis. Outcomes evaluated were occurrence of postoperative acute kidney injury/failure, requirement of any postoperative renal replacement therapy and short-term all-cause mortality rate. A meta-analysis was conducted and a pooled estimate of odds ratio (OR) was calculated using the inverse variance method. A total of 17 studies with a total population of 24 998 statin users and 22 082 non-statin users were included in the final analysis. PST resulted in a significantly lower incidence of renal replacement therapy in patients undergoing CABG (OR: 0.56 [0.41-0.76]) but not in isolated valve surgery (OR: 1.80 [0.73-4.44]). Also preoperative statin therapy resulted in a significantly lower postoperative mortality (0.72 [0.61-0.84]) irrespective of the type of surgery. There was no effect of preoperative statin therapy on the incidence of AKI in any of the sub-group of the patients. Patients undergoing CABG might derive benefit from preoperative statin therapy in terms of reducing the need for postoperative renal replacement therapy and mortality. However, the uncertainty concerning the reno-protective efficacy of preoperative statin therapy in patients undergoing isolated valve surgery needs further investigation.