The serum NT-proBNP is associated with all-cause mortality in geriatric hip fracture: a cohort of 1354 patients

Abstract

Geriatric hip fracture patients often have increased N-terminal prohormone of brain natriuretic peptide (NT-proBNP) levels. This study found a curved association between preoperative NT-proBNP level and all-cause mortality. There was an inflection point of NT-proBNP 781 ng/L in the saturation effect. Thus, NT-proBNP was a valuable indicator of all-cause mortality.

Purpose: To explore the relationship between N-terminal prohormone of brain natriuretic peptide (NT-proBNP) level and all-cause mortality in geriatric hip fractures and evaluate the possible predictive role of NT-proBNP level.

Methods: Consecutive older adult patients with hip fractures were screened between January 2015 and September 2019. Demographic and clinical characteristics of the patients were collected. Linear and nonlinear multivariate Cox regression models were used to identify the association between NT-proBNP levels and mortality. All analyses were performed using EmpowerStats and the R software.

Results: One thousand three hundred fifty-four patients were included in the study. The mean follow-up was 34.35 ± 15.82 months. Four hundred twenty-nine (31.68%) patients died due to all-cause mortality. The preoperative NT-proBNP was median 337.95 (range 16.09-20,123.00) ng/L. Multivariate Cox regression models showed a nonlinearity association between NT-proBNP levels and mortality in elderly hip fractures. An NT-proBNP of 781 ng/L was an inflection point in the saturation effect. When < 781 ng/L, NT-proBNP was associated with mortality (hazard ratio [HR] = 1.12, 95% confidence interval [CI]: 1.06-1.18, P < 0.0001), whereas at > 781 ng/L, NT-proBNP was not associated with mortality (HR = 1.00, 95% CI: 0.98-1.01, P = 0.4718). In the stratification analysis, the result was stable.

Conclusions: The NT-proBNP levels were nonlinearly associated with mortality in elderly hip fractures, and NT-proBNP of 781 ng/L was a valuable indicator of all-cause mortality.

Trial registration: ChiCTR2200057323.

Keywords: Cox regression; Elderly patients; Hip fracture; Mortality; NT-proBNP.