Association of NT-proBNP with renal function and albuminuria in non-dialysis chronic kidney disease patients

Background

Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular morbidity and mortality. However, the relationship between NT-proBNP, renal dysfunction, and albuminuria has not been sufficiently characterized in non-dialysis CKD populations after exclusion of overt cardiovascular confounders

Objective

To investigate the association between NT-proBNP levels, renal function stages, and albuminuria categories in a strictly selected non-dialysis CKD population.

Methods

This cross-sectional study included 300 non-dialysis CKD patients with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m².

Patients were classified according to eGFR as G3a (45–59; n=128), G3b (30–44; n=97), and G4–5 (<30; n=75). Albuminuria assessment was available in 275 patients and categorized as A1 (<30 mg/g; n=104), A2 (30–300 mg/g; n=83), or A3 (≥300 mg/g; n=88). NT-proBNP levels were compared across eGFR stages, albuminuria categories, and combined eGFR–albuminuria risk groups.

Results

The mean age was 63.4 ± 12.2 years, and 59.3% of patients were female. Hypertension was the most prevalent comorbidity (86%), followed by diabetes mellitus (38%) (Table 1).

NT-proBNP levels increased progressively with worsening renal function (p<0.001). Median (IQR) NT-proBNP values were 160 (89–249) pg/mL in G3a, 217 (108–447) pg/mL in G3b, and 416 (216–807) pg/mL in G4–5 patients (Figure 1). Post hoc analyses demonstrated significantly higher NT-proBNP levels in G3b compared with G3a (p=0.005), and in G4–5 compared with both G3a (p<0.001) and G3b (p=0.001). The prevalence of NT-proBNP ≥125 pg/mL increased stepwise across eGFR stages (58.6%, 69.1%, and 86.7%, respectively; p<0.001).

Across albuminuria categories, NT-proBNP levels differed significantly (p<0.001), with higher values observed in the A3 group compared with A1 and A2 (both p<0.001), while no difference was observed between A1 and A2 (p=0.778) (Table 2). Patients with combined advanced renal dysfunction (eGFR <45 mL/min/1.73 m²) and severe albuminuria (ACR ≥300 mg/g) exhibited markedly higher NT-proBNP levels than remaining patients (448 [207–968] vs. 180 [103.5–336] pg/mL; p<0.001) (Table 3).

NT-proBNP correlated inversely with eGFR (Spearman ρ = −0.408; p<0.001) and positively with serum creatinine (ρ = 0.244; p<0.001) and albuminuria (ρ = 0.221; p=0.001). In multivariable analysis, NT-proBNP emerged as an independent predictor of severe renal dysfunction (eGFR <30 mL/min/1.73 m²).

Conclusion

In this non-dialysis CKD cohort, NT-proBNP levels showed a strong association with renal function impairment and albuminuria severity. Notably, the prevalence of NT-proBNP ≥125 pg/mL was highest among patients with advanced CKD and severe albuminuria (ACR ≥300 mg/g). These findings indicate that NT-proBNP reflects integrated cardiorenal dysfunction beyond cardiac stress alone and may serve as a practical biomarker for early identification of high-risk CKD patients.For image description, please refer to the figure legend and surrounding text.For image description, please refer to the figure legend and surrounding text.