The Utility of Baseline Prognostic Nutritional Index (PNI) and Functional Status Among Hip Fracture and Distal Femur Fracture Patients

Baseline and functional and nutritional status are intertwined and associated with perioperative complications and mortality following orthopedic surgery, especially among geriatric patients. The prognostic nutrition index (PNI) is commonly used to appraise nutrition status. In many acute traumatic settings, the components of PNI can often be acutely influenced. Therefore, the aim of this of this study is to evaluate baseline functional status and PNI relationship with prolonged length of stay and 30-day mortality among geriatric distal femur and hip fracture patients. Patients ≥ 65 years with closed isolated Hip fracture and distal femur fractures (DFF) treated between 2005 and 2021 were identified by the National Surgical Quality Improvement Program (NSQIP) database. The primary outcome was comparison of prolonged length of stay and 30-day mortality across reported baseline PNI categories (< 35, 35-38, > 38) and functional status (fully dependent, partially dependent, totally independent). Univariable and multivariable Logistic regression analyses identified independent risk factors for each defined outcome. A total of 81,543 geriatric DFF and hip fracture patients were identified. The mean age was 79.5 (IQR: 74-85). Those with independent functional status reported a greater mean PNI of 35.7 compared to patients with partially (34.4) and fully (33.9) dependent status (p<0.001). Multivariable logistic regression observed a 20% (OR = 0.80, 95% CI = 0.77–0.83, p < 0.001) and 28% (OR = 0.72, 95% CI = 0.69–0.74, p < 0.001) decreased odds of a prolonged length of stay for patients with a PNI 35-38 and >38 when compared to those with a PNI <35, respectively. Partially dependent and fully dependent patients had 1.15-times (OR = 1.15, 95% CI = 1.11–1.20, p < 0.001) and 1.13-times (OR = 1.13, 95% CI = 1.04–1.23, p = 0.004) greater odds of a prolonged length of stay than patients who were fully independent. Additionally, patients with partial who reported partial and fully dependent functional status reported a respective 2.75 (OR = 2.75, 95% CI = 2.54–2.97, p < 0.001) and 4.48 (OR = 4.48, 95% CI = 3.94–5.10, p < 0.001) times increased odds of mortality compared to totally independent patients. This study underscores the importance of nutritional status in predicting outcomes in geriatric fracture patients while emphasizing the value of pre-operative functional status. PNI is a valuable but imperfect predictor of mortality, with functional status being a far more valuable prognosticator during the perioperative assessment. III.