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.