Clinical implications of the CKD epidemiology collaboration (CKD-EPI) equation compared with the modification of diet in renal disease (MDRD) study equation for the estimation of renal dysfunction in patients with cardiovascular disease

The CKD-EPI equation is more accurate than the MDRD equation in the general population. We performed this study to establish whether chronic kidney disease (CKD) is commonly recognized by clinicians and whether the CKD-EPI equation improves prognosis estimation in patients with chronic cardiovascular disease (CVD). We analyzed data on 12394 CVD patients consecutively examined at the Cardiovascular Center of Trieste (Italy) between November 2009 and October 2013. The outcomes were all-cause death and a composite outcome of death/hospitalization for CV events (D+cvH). CKD-EPI formula reclassified 1786 (14.4 %) patients between KDIGO categories compared to the MDRD: 2.3 % (n = 280) placed in a lower risk and 12.1 % (n = 1506) into a higher risk group. CKD, defined as eGFR-CKD-EPI formula <60 ml/min, was present in 3083 patients (24.9 %) but not recognized by clinicians in 1946 (63.1 % of patients with CKD). The lack of recognition of CKD was inversely proportional to the KDIGO class for both equations. There were 986 deaths and 2726 D+cvH during 24 months follow-up. The incidence of death and D+cvH was about twice as high in patients with unrecognized CKD than in those with normal renal function (31 % vs. 17.1 %, aHR: 1.35, 95 % CI: 1.15 to 1.60), even in those patients with eGFR-MDRD >60 but eGFR-CKD-EPI formula <60 (31.1 % vs 17.1 %, p < 0.001). CKD-EPI equation provides more accurate risk stratification than MDRD equation in patients with CVD. CKD was unrecognized in nearly two-thirds of these patients but clinical outcomes were similar in those for patients with recognized CKD.