Association between preoperative serum albumin levels and length of stay in elderly patients with hip fractures: A nonlinear relationship

Previous studies have provided relatively limited evidence in examining the impact of preoperative serum albumin levels on the length of hospital stay (LOS) in patients with hip fractures. This study aimed to elucidate the association between preoperative serum albumin levels and LOS in elderly patients with hip fractures. This retrospective cohort study included 1444 elderly patients undergoing surgical treatment for hip fractures at the Second People's Hospital of Shenzhen from January 2012 to December 2021. The main exposure variable was serum albumin level, and the outcome variable was LOS. A generalized additive model was used to identify the nonlinear relationship between serum albumin levels and LOS, and saturation effects were calculated using a two-piecewise linear regression model. Subgroup analysis was conducted using stratified logistic regression. The median LOS was 10 (8-15) days among all included patients. After adjusting for potential confounding factors (age, sex, comorbidities, hypertension, coronary heart disease, stroke, diabetes, duration of surgery, surgical method, intraoperative blood loss, red cell distribution width, estimated glomerular filtration rate, blood urea nitrogen, postoperative pneumonia, and transfer to ICU), a nonlinear relationship was found between serum albumin levels and LOS, with a turning point at 3.06. On the left side of the turning point, the effect size was not statistically significant (β = 1.84, 95% CI -1.00 to 4.68, P = .2042), while on the right side of the turning point, for every 1 g/dL increase in albumin, LOS decreased by 1.05 days (β = -1.05, 95% CI -1.90 to -0.20, P = .0162). A nonlinear relationship was observed between preoperative serum albumin levels and LOS in elderly patients with hip fractures. When albumin levels were >3.06 g/dL, they were negatively correlated with LOS. This has important implications for clinicians in the development of nutritional improvement strategies.