Prognostic value of circulating glypican-4 in patients with chronic heart failure with reduced ejection fraction

Abstract Background Chronic heart failure is one of the leading causes of hospitalization and mortality worldwide, with an ever-increasing prevalence. Glypican-4 (GPC4) is a cell surface protein part of the endothelial glycocalyx which is actively released into the circulation in the context of ischemia, inflammation, neurohumoral activity, and shear stress. The current literature on the association between circulating GPC4 and heart failure is limited and its prognostic value on top of established risk markers in chronic heart failure is unknown. Purpose In the present study, we aim to investigate the prognostic value of circulating GPC4 on clinical outcomes in a contemporary cohort of patients with stable chronic heart failure with reduced ejection fraction (HFrEF). Methods Symptomatic outpatients with stable chronic HFrEF were consecutively enrolled in a prospective cohort study. Circulating serum GPC4 levels were assessed using an enzyme-linked immunosorbent at baseline. Patient outcomes were retrieved from medical and health insurance records. Results We enrolled 205 patients with a median (interquartile range) age of 66 (59-74) years, with 22% females. Median left ventricular ejection fraction (LVEF) was 37 (30-43)%, median estimated glomerular filtration rate (eGFR) was 64 (48-80) ml/min/1,73 m2, median N-terminal pro-brain natriuretic peptide (NT-proBNP) was 964 (336-2173) pg/ml, median interleukin 6 (IL6) was 4.7 (3.2-7.9) pg/ml, and median GPC4 was 1553 (1034-1950) pg/ml. During a median follow-up of 4.7 (4.0-5.3) years, 46 patients (22%) were hospitalized due to worsening heart failure (WHF), 18 patients (9%) died of cardiovascular (CV) cause, and 58 patients (28%) died of any cause. In univariate Cox-regression, serum GPC4 levels predicted WHF (HR 1.57, 95%CI 1.29-1.92, p<0.001), CV death (HR 2.07, 95%CI 1.56-2.74, p<0.001), and all-cause mortality (HR 1.93, 95%CI 1.59-2.34, p<0.001). The association between serum GPC4 levels and both, CV death (HR 1.69, 95%CI 1.04-2.86, p=0.048) and all-cause mortality (HR 1.56, 95%CI 1.14-2.14, p=0.006) remained significant in a multivariable Cox-regression model adjusted for age, sex, eGFR, IL6, NT-proBNP, and LVEF. Conclusion In patients with stable chronic HFrEF, circulating GPC4 is significantly associated with cardiovascular outcome and is an independent predictor of all-cause mortality. The potential prognostic value in clinical routine of GPC4 should be addressed in prospective studies.