Admission Red Cell Distribution Width–Albumin Ratio and 1-Year Mortality in Chronic-Wound Inpatients: Prediction-Model Development, Internal Validation, and Exploratory Temporal Evaluation

Objective: To identify admission-day factors associated with 1-year mortality in adults hospitalized with a chronic wound of any etiology, and to develop and internally validate a model pairing the red cell distribution width–albumin ratio (RAR) with the age-adjusted Charlson Comorbidity Index (ACCI). Approach: In a single-center retrospective cohort reported per Strengthening the Reporting of Observational Studies in Epidemiology and Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis + Artificial Intelligence, adults admitted for a chronic wound (2021–2024) were analyzed at first admission ( n = 584). Admission markers were compared by area under the curve; a logistic model of RAR and ACCI was internally validated by bootstrapping and applied unchanged to a later same-center cohort ( n = 124) for exploratory temporal evaluation. The primary outcome was 1-year all-cause mortality. Results: Fifty-three patients (9.1%) died within 1 year. Pressure ulcers carried the highest mortality; the strongest comorbid markers were prior intensive care, dementia, and cardiopulmonary disease. RAR discriminated best, ahead of its components, albumin and red cell distribution width. The two-variable model showed strong discrimination (optimism-corrected C-statistic 0.855) and good calibration, stratifying patients into low-, intermediate-, and high-risk tiers (observed mortality 1.3%, 9.0%, and 36.8%); a high admission RAR (≥5.2) or low albumin (<3.0 g/dL) likewise flagged high-risk patients. In an exploratory same-center temporal evaluation, discrimination was similar; calibration was imprecise. Innovation: This provides a simple, admission-day, patient-level 1-year mortality model for mixed-etiology chronic-wound inpatients, a group for whom admission-day mortality tools have been lacking. Conclusion: Two routine admission-day variables estimated 1-year mortality in chronic-wound inpatients well enough to separate risk groups on the day of admission.