Altered seric levels of albumin, sodium and parathyroid hormone may predict early mortality following hip fracture surgery in elderly

Purpose To analyse a wide set of routine laboratory parameters at admission to predict mortality within 30 post-operative days in elderly patients with hip fracture, as well as calculate the critical values of those biomarkers. Method Data of 994 patients older than 65 years with hip fracture were analysed of which 89 (8.2%) died within 30 post-operative days. Variables described in the literature with potential influence on early mortality were collected, including demographics, fracture type, American Society of Anesthesiologists score, Charlson's comorbidity index and pre-operative Hodkinson's mental test and the Katz index for activities of daily living. In addition, an exhaustive collection of biomarkers from routine blood testing at admission was performed. Critical levels of biomarkers were calculated by the method of area under ROC curve. Results At admission, early mortality group had significantly higher Charlson's index (p = 0.001) and lower the Katz index (p = 0.001). The surgical delay also was significantly longer in that group (p = 0.001). In univariate analyses, serum concentration at admission of total protein (p = 0.004), albumin (p = 0.001), sodium (p = 0.001), and parathyroid hormone (PTH) (p = 0.001) were significantly different between both groups. In multivariate analysis, serum albumin < 2.9 g/dL (p = 0.013), sodium < 127 mEq/L (p = 0.035) and PTH > 65 pg/mL (p = 0.005) were predictors of early mortality. The three biomarkers together accounted for 67% of the variability in early mortality. Conclusion The association of altered levels at admission of serum concentration of albumin, sodium and PTH was predictor of early mortality following hip fracture surgery in elderly patients.