Incremental Prognostic Value of Albumin-Anchored Inflammatory Ratios Beyond a SOFA-Based Model in a Medical ICU: A...

Background/Objectives: We compared three albumin-anchored ratios calculated from measurements obtained during the first 24 h, C-reactive protein (CRP)-to-albumin (CAR), procalcitonin-to-albumin (PAR) and lactate-to-albumin (LAR), as predictors of intensive care unit (ICU) mortality beyond an established severity model. Methods: Eligibility required an ICU stay reaching 24 h and a complete early work-up; 372 of 1352 screened admissions qualified, with each ratio using the worst component values in that window. Incremental value over a base model (Sequential Organ Failure Assessment (SOFA) score, sex, age-adjusted Charlson index) was assessed by change in the area under the curve (AUC; DeLong test), reclassification metrics (NRI, IDI) and calibration, with alternative baselines and outcomes, multiplicity adjustment, and selection weights from the excluded admissions. Results: Of 372 patients, 248 (66.7%) died. As standalone predictors, CAR (0.671), PAR (0.689) and LAR (0.642) were indistinguishable and inferior to SOFA (0.730). Only CAR significantly improved AUC discrimination (ΔAUC +0.030, p = 0.024; NRI +0.39; IDI +0.042); PAR and LAR did not significantly improve AUC discrimination. Entered together, CAR remained independent (aOR 1.52, 1.15-2.03), while PAR did not (1.20, 0.89-1.63). The cohort was sicker than the 626 patients excluded for incomplete work-up; after weighting, CAR stayed independent (aOR 1.47) but ΔAUC fell to +0.018. The increment was significant against SOFA alone (+0.033) but not against baselines including admission diagnosis or organ support; it remained significant after Benjamini-Hochberg but not Bonferroni adjustment. With in-hospital mortality it was larger (+0.044), but PAR then also retained independence. Conclusions: The first 24 h CAR provided a well calibrated improvement beyond a parsimonious SOFA-based model, but the increment was small and not robust to richer baselines or to multiplicity correction, and no subgroup-specific claim is supported. These hypothesis-generating findings need prospective validation.