Analysis of risk factors for hypoproteinemia after total hip arthroplasty and construction of a nomogram: A retrospective study

Postoperative hypoalbuminemia (POHA) remains one of the major complications following total hip arthroplasty (THA) in patients with end-stasge hip disease. Identifying factors that can reduce the incidence of POHA is crucial for improving clinical outcomes in these patients. Our study aimed to develop and validate a nomogram that can pre-operatively quantify an individual patient’s risk of POHA. We retrospectively reviewed patients aged ≥65 years who underwent primary unilateral THA between January 2021 and December 2022. Inclusion criteria were: age ≥ 65 years, primary unilateral THA, pre-operative serum albumin > 30 g/L, and no history of liver disease, nephrotic syndrome or malignancy that could affect albumin metabolism. Exclusion criteria were: revision or secondary THA, incomplete medical records, or missing key peri-operative data. The primary outcome was the occurrence of POHA, defined as serum albumin < 30 g/L. Univariate and multivariate regression analyses were performed to identify independent risk factors for POHA, followed by the development of a nomogram. The discriminative ability, predictive accuracy, and clinical utility of the nomogram were evaluated using the area under the curve, calibration curves, and decision curve analysis. Among the 419 THA patients, POHA occurred in 130 cases (16.9%). Multivariate regression analysis revealed that female sex (odds ratio OR = 2.74, 95% confidence interval CI: 1.31–5.72, P = .007), longer operative time (OR = 1.02, 95% CI: 1.01–1.03, P = .006), elevated erythrocyte sedimentation rate (OR = 1.03, 95% CI: 1.01–1.05, P < .001), lower preoperative serum albumin (OR = 0.80, 95% CI: 0.72–0.88, P < .001), and higher alkaline phosphatase levels (OR = 1.01, 95% CI: 1.01–1.02, P = .045) were independent risk factors for POHA. A nomogram prediction model was constructed based on these 5 variables. The area under the curve values for the training and validation cohorts were 0.81 (95% CI: 0.74–0.87) and 0.76 (95% CI: 0.65–0.88). Female, prolonged operative time, elevated erythrocyte sedimentation rate, and higher alkaline phosphatase levels were identified as risk factors for POHA after THA, while higher preoperative serum albumin was a protective factor. Orthopedic surgeons should carefully consider POHA and its influencing factors when optimizing perioperative THA management.