Associations Between Routine Blood‐Derived Inflammatory Markers and 14‐Day Readmission After Total Hip Arthroplasty: An Exploratory Study

Objective Early readmission following total hip arthroplasty ( THA ) is not uncommon and impacts patient outcomes and healthcare costs. However, easily accessible biomarkers for early identification of high‐risk patients remain limited. This study aims to evaluate the association between various blood component‐derived ratios and 14‐day readmission after THA . Methods Data from the Chang Gung Medical Research Database ( CGRD ) from 2014 to 2022 were retrospectively analyzed. Patients ≥ 20 years old who underwent primary THA by a single surgeon were included. The primary outcome was 14‐day readmission. Five hematologic markers were evaluated: monocyte‐to‐albumin ratio ( MAR ), red cell distribution width ( RDW )‐to‐albumin ratio ( RAR ), hemoglobin‐to‐albumin ratio ( HAR ), leukocyte‐to‐albumin ratio ( LAR ), and RDW ‐to‐platelet ratio ( RPR ). Ratios were calculated from blood collected within 1 month before to 1 week after surgery. Receiver operating characteristic ( ROC ) Curve analysis was used to determine their optimal thresholds, and multivariable logistic regression assessed associations between these markers and readmission risk. Results A total of 307 patients were included in the analysis. Among the ratios evaluated, only high RPR (≥ 0.10; aOR = 5.92, 95% CI : 2.19–16.00, p = 0.001) was significantly associated with increased risk of 14‐day readmission after adjustment in the multivariable analysis. Conclusion RPR is independently associated with 14‐day readmission following THA in this exploratory study. As an easily obtainable marker, it may aid postoperative risk stratification, and the findings provide a foundation for future multicenter prospective investigations incorporating more granular perioperative factors and additional biomarkers before clinical application.