Evaluation of discriminative capacity of two formulas of CKD-EPI to predict complications after the first episode of heart failure with preserved ejection fraction

Background: Determining the prognosis of heart failure with preserved ejection fraction (HFpEF) is problematic, as the ejection fraction cannot be used. Formulae that estimate glomerular filtration rate (eGFR) may be potential prognosticators for this condition, since renal dysfunction is a well-known predictor of poor outcomes of all forms of heart failure. Methods: A prospective observational study of 117 HFpEF patients (average age 71.6 +/- 9.1 years; 65.8% women) who had eGFR determined after their first episode of cardiac decompensation by two different chronic kidney disease epidemiology collaboration (CKD-EPI) equations. The ability to predict hospitalizations and mortality over 24 months by the two equations were compared. Results: The CKD-EPI formula based on serum creatinine only performed poorly. However, the CKD-EPI equation that used both serum creatinine and serum cystatin C was associated with unfavorable outcome: eGFR <45 mL/min/1.73 m(2) predicted 24-month mortality (HR=4.21 [1.32; 13.43], p=0.02) and the combined endpoint of mortality and hospitalization (HR 2.45 [1.42; 4.22], p=0.001).. Conclusions: eGFR by the CKD-EPI equation based on serum creatinine and cystatin C levels, but not by the CKD-EPI creatinine only equation, predicts the outcome of HFpEF patients.