Association of an age-albumin-red cell distribution width score with 28-day in-hospital mortality in emergency department patients with suspected sepsis

This study evaluates the performance of a simple age-albumin-red cell distribution width (AAR) score for stratifying 28-day in-hospital mortality risk in an operational cohort of adult emergency department (ED) patients with suspected sepsis and in a later-period subgroup. This single-center retrospective cohort study analyzed an operational ED suspected-sepsis cohort of 852 adults defined by a modified early warning score of 5 or higher plus an infection-related ED discharge diagnosis from 2022 to 2025. The AAR score assigned one point each for age ≥ 75 years, albumin < 3.0 g/dL, and red cell distribution width ≥ 14.5%; scores ≥ 2 indicated high risk. Performance was assessed using the area under the receiver operating characteristic curve (AUROC), classification metrics, calibration, and exploratory clinical net benefit overall and across chronological study periods. Overall, 98 patients (11.5%) died within 28 days. The AAR AUROC was 0.787 (95% confidence interval [CI]: 0.740–0.833) overall and 0.778 (95% CI: 0.703–0.852) in 2024 to 2025; paired comparison did not demonstrate greater discrimination than continuous albumin alone (difference, 0.013; 95% CI: −0.074–0.100; P  = .770). However, mortality increased stepwise across AAR categories (2.2%, 7.4%, 21.7%, and 49.2%), and this gradient was preserved in the later-period cohort (1.4%, 6.6%, 15.9%, and 41.4%). The earlier-period equation overpredicted absolute mortality risk in the later period. The AAR score combined 3 routinely available variables into 4 ordinal groups with a consistent mortality gradient across study periods. Its simple 0 to 3-point structure supports further external evaluation as an adjunct to early ED risk stratification. Patient-level probability estimation and decision-support use require additional validation and recalibration.