t’s time for a fivesome. Commentary to: “The predictive value of five glomerular filtration rate formulas for long-term mortality in patients undergoing coronary artery bypass grafting” Coronary artery disease is an extremely common condition and coronary artery bypass-grafting is still one of the most important therapeutic strategy to treat it. Chronic kidney disease is often affecting patients with CAD. Nevertheless, the literature is still debating what formula estimate the best the glomerular filtration rate in patients undergoing CABG. Indeed, the formulas used in clinical practice have some differences some are more accurate in patients with diabetes, while there are some bias given by age and body mass index. In cardiac surgery, the choice of the most fitting formula to evaluate GFR has important clinical implication and, up to now, three formulas have been compared at most. Eilon Ram et al. present a retrospective study which compares the 5 most used formulas (CG, MDRD, CKD-EPI, Mayo, and IB) to derive GFR to evaluate the one with the best accuracy in predicting long-term mortality. In order to do so, they divided 3744 patients in three groups according to the estimated GFR by means of all 5 formulas: significant CKD according to all formulas, non-significant CKD according to all formulas and discordant results (meaning that at least one formula gave normal GFR and at least one formula gave abnormal GFR). Patients with the highest mortality were the ones with significant CKD according to all formulas.