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Kidney Week

Abstract: PO0440

Elderly Patients Are Likely to Have Faster CKD Progression if Plasma Brain Natriuretic Peptide (BNP) Is Elevated

Session Information

Category: CKD (Non-Dialysis)

  • 2101 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

  • Morimoto, Shiho, Mihara Red Cross Hospital, Mihara, Hiroshima, Japan
  • Tanaka, Hiroshi, Mihara Red Cross Hospital, Mihara, Hiroshima, Japan
Background

Elderly CKD patients have been mostly believed that they have slower decline in eGFR than younger individuals. However, this is not the case, especially when the patient has well-known factor(s) that accelerate(s) CKD progression, such as cardiac dysfunction. Plasma concentration of brain natriuretic peptide (BNP) is often elevated in patients with cardiac dysfunction and is known to be associated with higher mortality. This study was conducted to find out whether plasma BNP level can be used to predict future decline in eGFR.

Methods

A hospital-wide study with all the laboratory data for a period of 4 years and 2 months was performed. Non-dialysis CKD patients (median eGFR <60 mL/min/1.73m2) with an age 65 or more in whom the eGFR slope was obtained over 731 days or more with BNP measured at least three times were retrieved. An eGFR slope per each patient was calculated and its relationship with plasma BNP level and other factors was assessed. Statistical analysis was done with R 3.6.0 on Ubuntu.

Results

A total of 339 patients (M:F = 154:185, age 65-102 (median 84) years) were included whose initial BNP was 130.0+-184.2 (0-1,641.5, median 75.6) pg/mL . A “random forest” analysis, one of the multivariate analyses, was performed using an R package {randomForest}, in order to elucidate risk factors associated with faster decline in GFR; factors with the highest importance, i.e., with the highest change in Gini indices, were found to include initial eGFR, initial BNP and variability of BNP. With linear regression analysis, the eGFR slope was significantly associated with initial eGFR and initial BNP (P<0.0001). Patients with higher-than-average initial BNP (>130.0 pg/mL and higher-than-average initial eGFR (>49.1 mL/min/1.73m2) had significantly faster decline in eGFR than the rest of the population (-3.83+-4.62 vs -1.72+-3.57, P=0.0001). A combination of initial eGFR and initial BNP correctly differentiated the fastest quartile from the rest in 72.9% of the population.

Conclusion

Elevated plasma BNP might predict faster decline in eGFR in the elderly CKD patients.