The N‑terminal pro-brain natriuretic peptide (NT-proBNP) has an important prognostic value in chronic renal insufficiency; however, most studies have been conducted in patients with end-stage renal disease (ESRD). In this study we evaluated the prognostic significance of NT-proBNP in very old patients with stage 3 chronic kidney disease (CKD) and compared its prognostic value in CKD3a versus CKD3b patients.
Patients (age ≥80 years old) hospitalized with stage 3 CKD from 2007 to 2010 who were eligible for this prospective study underwent follow-up examinations in 2015. The examinations included measurements of anthropometric characteristics, blood pressure, plasma NT-proBNP, creatinine, and lipids. End-point events were all-cause death and major adverse cardiac events (MACEs).
A total of 168 patients (mean age 87.4 ± 2.9 years, range 80–99 years) were included in the analysis (CKD3a, n = 117; CKD3b, n = 51). The results showed that CKD3b was associated with lower hemoglobin levels, higher NT-proBNP levels and a higher rate of hypertension compared with CKD3a. After a median follow-up of 3.8 years (interquartile range 1.5–6.1 years), a higher NT-proBNP level was associated with a higher risk of all-cause death (hazard ratio HR 1.986, 95% confidence interval CI 1.276–2.819, p = 0.028) and MACEs (HR 2.872, 95% CI 1.241–6.644, p = 0.014) after adjusting for age, sex, and traditional risk factors; however, a subgroup comparison showed that elevated NT-proBNP levels were associated with a higher risk of all-cause death (HR 2.350, 95% CI 1.906–6.091, p = 0.039) and MACEs (HR 3.025, 95% CI 1.024–8.940, p = 0.045) in CKD3a but not CKD3b.
Levels of NT-proBNP increased with decreased renal function in very old patients with stage 3 CKD; therefore, NT-proBNP is an independent predictor for all-cause death and MACEs in these patients but has a greater prognostic value in CKD3a than in CKD3b.