B-type natriuretic peptide and subsequent kidney function decline in the general population with preserved kidney function.

Elevated B-type natriuretic peptide (BNP) concentrations reflect cardiac stress and are associated with adverse kidney outcomes in patients with established chronic kidney disease (CKD). However, whether modest elevations in BNP are associated with subsequent deterioration in kidney function among individuals with preserved kidney function remains unclear. We investigated 15,071 Japanese adults with an estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m² and without overt cardiac disease who participated in annual health check-ups. Plasma BNP was measured at baseline, and the primary renal outcome was the first occurrence of an eGFR <60 mL/min/1.73 m². Median baseline BNP was 8.6 pg/mL (6.9 in men and 11.4 in women). During a median follow-up of 2154 days (95,368 person-years), 2824 participants reached the primary renal outcome (29.6 per 1000 person-years). Event rates increased across sex-specific BNP quartiles (24.0, 26.8, 29.7, and 40.1 per 1000 person-years from the first to fourth quartiles, respectively). After adjustment for established risk factors and baseline serum creatinine, higher baseline BNP remained significantly associated with the primary renal outcome (HR for the fourth vs. first quartile, 1.659; 95% CI, 1.473-1.868). Higher baseline BNP was also associated with a more negative annual eGFR slope. In a sensitivity analysis incorporating dipstick proteinuria, the association remained significant. Higher baseline BNP is therefore associated with subsequent deterioration in kidney function among individuals with preserved baseline eGFR.