Plasma Proteomic Profiling of Comorbid and Noncomorbid COVID-19 Patients in ICU

Type 2 Diabetes (T2D) and hypertension (HTN) are common comorbidities in severe COVID-19, yet their specific impact on proteomic recovery remains unclear. This study analyzed plasma protein signatures of critical COVID-19 patients with and without these comorbidities (COVID-only group [COG] and COVID comorbid group [CTHG]) on the first and last days of ICU stay. Proteomic analysis revealed a systemic shift characterized by upregulated immune responses and downregulated metabolic processes at admission across all patients. Survival was fundamentally defined by the restoration of homeostasis; liver-derived proteins─including LPA, TTR, and AHSG─were initially suppressed but rebounded significantly in survivors. This homeostatic recovery was impaired in CTHG compared to COG, with CTHG survivors showing attenuated recovery of metabolic markers. Distinct mortality-associated signatures also emerged between groups. COG nonsurvivors exhibited liver failure and severe hemolysis marked by persistent suppression of haptoglobin (HP). In contrast, CTHG mortality was driven by lipid metabolism dysregulation, with CD5L and APOA2 levels dropping specifically in comorbid nonsurvivors, often accompanied by a paradoxical elevation in APOA4─likely reflecting impaired renal clearance rather than restored lipid homeostasis. These findings indicate that preexisting T2D and HTN hinder physiological resolution of metabolic and lipid dysregulation, providing proteomic evidence for distinct mortality risks associated with failure to restore metabolic homeostasis in comorbid COVID-19 patients.