Relationship between GDF-15, urinary sodium and markers of renal function in patients with chronic heart failure

Abstract

Abstract Background Patients with heart failure (HF) often have altered renal function. Urinary sodium is a marker of diuretic resistance and is associated with a worse prognosis in HF. Growth differentiation factor-15 (GDF-15) is a marker of oxidative stress and inflammation and is a prognostic predictor in HF. Objectives We sought to assess the relationship of GDF-15 with renal function parameters and with urinary sodium in patients with chronic HF. Methods We undertook a cross-sectional study of patients with HF from specialized outpatient clinic. Patients with signs and symptoms of HF and LVEF <50% were included. An echocardiogram was performed and blood samples were collected, which were frozen for the final study, where the performance of GDF-15 in the prediction of renal outcomes in HF will be evaluated. The dosage of NT-proBNP was performed using the Elecsys® system (Roche, Basel, Switzerland) and GDF-15 by the sandwich immunoassay method with monoclonal antibodies (Elecsys®, Roche, Basel, Switzerland). Analysis of the relationship between GDF-15 and baseline renal parameters was performed. Correlation analysis was performed between GDF-15 and continuous variables, using the Spearman method. Results Sixty-seven patients were included. The etiologies of HF were hypertension, diabetes mellitus, alcoholic cardiomyopathy and idiopathic cardiomyopathy. Forty-one (61.2%) individuals were male, with a mean age of 61±13 years. Median GDF-15 values were 1413 pg/mL (interquartile range 1044–2554). Patients with GDF-15 values above the median had lower urinary sodium values (88 mEq/L [53–121] vs 112 [76–171], p=0.06), lower glomerular filtration rate (GFR) (63.9±29.1 vs 91.2±25 mL/min/1.73 m2, p=0.001) and higher creatinine levels (1.32 mg/dL [0.85–1.71] vs 0.91 [0.78–1.08], p<0.001). There was no significant difference in relation to urinary albumin (21 mg/L [7–126] vs 15.1 [5.8–41], p=0.30). The urinary albumin/creatinine ratio was higher in the group above the median, but did not reach statistical significance (38 mg/g [11–110] vs 12.5 [4.9–29], p=0.13). There was a direct correlation between GDF-15 and creatinine (r=0.56, p<0.001) and an inverse correlation with urinary sodium (r=−0.39, p=0.005) and with GFR (r=−0.55, p<0.001). Conclusion GDF-15 correlated with lower urinary sodium levels and worse kidney function in patients with chronic HF. Future studies should address whether GDF-15 is a predictor of worsening renal function overtime. Funding Acknowledgement Type of funding sources: None.