Femoral artery calcification predicts hip fracture in maintenance hemodialysis patients

Abstract

Femoral artery calcification (FAC) is a significant predictor of hip fractures in hemodialysis patients. A higher FAC score is associated with increased fracture risk and poor survival outcomes. Identifying FAC through radiographic assessment may improve fracture risk stratification and clinical management in this high-risk population.

Purpose: Patients with end-stage renal disease (ESRD) on hemodialysis (HD) are at increased risk for vascular calcification (VC) and bone fractures. While previous studies have linked aortic calcification with hip fractures, the relationship between medium-caliber artery-femoral artery calcification (FAC) and fall-related hip fractures in HD patients remains unclear.

Methods: We retrospectively analyzed 170 HD patients who experienced falls and sought treatment in the emergency department (ED) between 2007 and 2014. The FAC score, representing the severity of femoral artery calcification, was calculated as the ratio of the total length of calcification plaques to the length of the femoral vessel visible on plain radiographs of the hip and femur. A logistic regression model assessed the association between FAC score and hip fracture risk, and receiver operating characteristic curve analysis evaluated its predictive power.

Results: Among the 130 patients meeting inclusion criteria, 55 had fall-related hip fractures. The incidence rate of hip fractures among dialysis patients was 6.18 cases per 1000 person-years by dividing the total number of hip fracture events by the cumulative dialysis duration (in years) of all enrolled patients. Fracture patients were older and had lower serum creatinine, sodium, and albumin levels but higher aspartate aminotransferase levels. The fracture group also had a higher FAC score (0.47 [IQR, 0.28 - 0.76] vs. 0.00 [IQR, 0.00 - 0.40], p < 0.001). Multivariable analysis identified old age, heart failure with reduced ejection fraction (EF), and higher FAC scores as independent risk factors for hip fractures. Survival curves showed increased mortality among patients with higher FAC scores and hip fractures (p < 0.01).

Conclusion: High FAC scores were associated with an increased risk of hip fractures in HD patients, independent of traditional risk factors, and were linked to poor survival outcomes.

Keywords: Dialysis; Femoral artery calcification; Hip fracture; Vascular calcification.

Fig. 1

Flowchart depicting the selection process of hemodialysis patients without and with hip fractures

Fig. 2

A representative radiographic image illustrates the measurement of the FAC score. The FAC score was calculated as the total length of calcification plaques divided by the length of the femoral vessel seen on plain radiographs

Fig. 3

ROC curve analysis for the prediction of a hip fracture. ROC curves using three different parameters to predict hip fractures. The AUC for each color represents the overall performance of that parameter in predicting hip fractures

Fig. 4

Kaplan–Meier survival curves for all-cause and cardiovascular mortality in hemodialysis patients. Patients with FAC scores ≥ 0.27 had significantly lower cumulative survival for all-cause mortality (p < 0.01), but no significant difference was observed for cardiovascular mortality. Fracture patients showed significantly lower cumulative survival for all-cause mortality (p < 0.0001), while no significant difference was observed for cardiovascular mortality (p = 0.43)