Prognostic nutritional index (PNI) is an independent risk factor for the postoperative mortality in geriatric patients undergoing hip arthroplasty for femoral neck fracture? A prospective controlled study

Abstract

Introduction: Hip fracture is very common in advanced ages, and it is very likely that this condition is accompanied by nutritional deficiencies. The aim of this study was to investigate the effect of prognostic nutritional index (PNI) on postoperative mortality in geriatric patients who underwent hip arthroplasty for femoral neck fracture.

Materials and methods: Geriatric patients (aged ≥ 70 years) who underwent hip arthroplasty for femoral neck fracture were prospectively recruited. The patients' demographic data, time until surgery, total hospital stay, perioperative blood transfusion, duration of surgery and anesthesia, serum albumin level, total lymphocyte count, PNI value, and first-year mortality were examined. They were divided into two groups as patients who died and those who did not die within the 1st year, and between-group comparisons for continuous and categorical variables were made using independent t test and Chi-square test, respectively. Receiver operating characteristic (ROC) curve was constructed, and a cutoff value for PNI was determined based on sensitivity and specificity values.

Results: The total number of participants was 124. The mean age was 80.40 ± 7.19 years: 77 (62.1%) were female and 47 (37.9%) were male. PNI was statistically significant for 1-year mortality in multivariate Cox regression analysis (p < 0.05). According to ROC curve analysis, the area under the curve for PNI level was found to be 0.764 (95% CI 0.670-0.857), and this value was statistically significant (p < 0.001). The sensitivity and specificity for the 38.4 cutoff value were 83.9% and 39.8%, respectively. The mean age, time after surgery, total hospital stay, and preoperative blood transfusion need were found to be statistically higher in the patients with low PNI levels (≤ 38.4) than those in the other patients (> 38.4) (p < 0.05 for all).

Conclusion: PNI seems to be an independent risk factor on mortality after hip fracture surgery in geriatric patients. PNI is a preventable and correctable risk factor that affects patient survival.

Keywords: Femoral neck fracture; Hip fracture; Mortality; Nutrition; Prognostic nutritional index.