Comparative Effects of Mineralocorticoid Receptor Antagonism on Organ Dysfunction in COVID-19-Associated ARDS

Background/Objectives: Diuretics are recommended for hemodynamically stable patients with COVID-19-associated acute respiratory distress syndrome (ARDS) who have a positive fluid balance. However, furosemide use may be limited by hypokalemia in this population. We aimed to evaluate the clinical and biochemical effects of spironolactone in critically ill patients with COVID-19-associated ARDS. Methods: In this retrospective cohort study, 60 patients with COVID-19-associated ARDS admitted to the intensive care unit (ICU) between March and May 2020 were grouped according to diuretic therapy (furosemide vs. spironolactone). Patients were followed for five days (T0–T4). Demographic characteristics and clinical/laboratory parameters were recorded. A two-sided p value < 0.05 was considered statistically significant. Results: Thirty-one patients received furosemide (F group) and 29 received spironolactone (S group). On day 5, in the F group, cumulative fluid balance and serum sodium increased significantly over time (p < 0.05). Lactate increased significantly over time in both groups (p < 0.05). N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels increased significantly from T0 to T4 in the F group (p < 0.05). Conclusions: Spironolactone use was associated with a more favorable trajectory of organ dysfunction and improved volume, electrolyte, and cardiac stress marker dynamics compared with furosemide in patients with COVID-19-associated ARDS. Although confirmation in larger prospective studies is needed, spironolactone may be considered a reasonable diuretic alternative in selected patients, particularly when potassium preservation and avoidance of hypernatremia are clinical priorities.