Clinical Impact of Indirect Markers of Renal Function in Elderly Patients With Hip Fracture

Abstract

Introduction: There are risk factors associated with mortality in patients older than 70 years with hip fracture, including kidney function. However, indirect formulas to calculate glomerular filtration rate are not validated in patients older than 70 years. We analyzed whether the formula hematocrit, urea, and gender (HUGE) can be used as a prognostic factor. Material and Methods: A retrospective cohort study of 88 patients older than 70 years with a diagnosis of hip fracture. At admission, clinical and biochemical parameters were measured and glomerular filtration rate by Cockcroft-Gault, Modification Of Diet In Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and HUGE value. Accuracy to assess long-term mortality was analyzed with receiver–operating curve analysis. Cox regression analysis was performed to identify risk factor for mortality. Results: Sample included 88 patients; overall mortality was 13.63%, 17.85%, 28.57%, and 75.85% at 6 months, 1, 2, and 3 years, respectively. There was no significant difference in glomerular filtration rate by different formulas, contrary to HUGE, with higher values in the mortality group (1.83 ± 6.38 vs −2.61 ± 2.70, P = .0001). Survival was lower in patients with higher HUGE values (22.7 months, 95% confidence interval [CI] 16.1-29.5 vs 32.9 months, 95% CI 30.2-35.7; P ≤ .001). In the Cox regression analysis, a negative HUGE value is associated with lower mortality (hazards ratio = 0.238; 95% CI 0.568-0.099). Conclusion: The HUGE formula is an independent risk factor for mortality in elderly patients with hip fracture, but not the glomerular filtration rate determined by Cockcroft-Gault, MDRD, and CKD-EPI.