Combined ACEI and ARB therapy and ICU mortality in critically ill COVID-19 patients: a retrospective cohort study

In this observational ICU cohort, dual RAAS blockade was associated with lower in-hospital mortality, although causal inference is limited by the retrospective design and incomplete pharmacologic exposure data. Early bicarbonate increase may reflect renal adaptive capacity and has potential prognostic value. Prospective controlled studies are needed to clarify the clinical relevance of RAAS modulation and metabolic biomarkers in severe COVID-19.