Prognostic impact of kidney function in a large contemporary ambulatory heart failure cohort

Kidney dysfunction is common in chronic heart failure (CHF), but its prognostic significance in contemporary populations remains uncertain. We evaluated 1-year outcomes according to kidney function stage and the prognostic role of the estimated glomerular filtration rate (eGFR).

We analyzed 1105 patients with CHF enrolled in the CARDIOREN Registry (13 centers, 2021-2022). Kidney function was categorized according to CKD-EPI eGFR (≥ 60, 30-59, < 30 mL/min/1.73 m²). The primary endpoint was the composite of all-cause death or worsening heart failure at 1 year; all-cause mortality was analyzed separately. Associations were assessed using multivariable Cox regression models with fractional polynomial modeling.

Median age was 75 years, 63% of patients were men, and 38% had heart failure with preserved ejection fraction. Overall, 59% had eGFR < 60 mL/min/1.73 m². At 1 year, the composite endpoint occurred in 24% of patients, and all-cause mortality occurred in 13%. Event rates increased progressively with worsening kidney function categories for the primary endpoint (11%, 31%, and 38%; P < .001) and for all-cause mortality (4%, 16%, and 26%; P < .001). In multivariable analysis, N-terminal pro-B-type natriuretic peptide, hemoglobin, and furosemide-equivalent dose were independently associated with both outcomes. Hemoglobin showed a U-shaped association, with higher risk at both low and high concentrations. CA125 was independently associated with all-cause mortality. eGFR was not independently associated with the composite endpoint but remained independently associated with all-cause mortality, showing a nonlinear inverse relationship.

In this contemporary CHF population, worse kidney function identified patients with a more adverse clinical profile and poorer outcomes, although these associations were attenuated after adjustment for congestion markers and disease severity.