Renin and 1-year mortality in critically ill patients with ARDS: trajectories, discrimination, and survival analysis

We investigated whether early and serial plasma renin concentration (PRC) is associated with 1-year mortality in critically ill patients with COVID-19-related acute respiratory distress syndrome (ARDS).

We conducted a single-center retrospective cohort study in a tertiary intensive care unit, including exclusively patients with COVID-19-related ARDS. PRC was measured at 72 h (T0), 120 h (T1), and 168 h (T2) after intensive care unit (ICU) admission. Chronic renin-angiotensin-aldosterone system (RAAS) inhibitors (ACEi/ARB) were discontinued on admission. The primary endpoint was 1-year mortality.

The analysis set included 104 mechanically ventilated patients with COVID-19-related ARDS and available 1-year outcome; 48/104 (46%) died within one year. Higher renin was associated with 1-year mortality at T0 (OR 1.94; p = 0.002), T1 (OR 1.69; p = 0.014), and T2 (OR 2.52; p < 0.001). Kaplan-Meier curves by renin tertiles showed significant separation at T0 and T2 (log-rank p < 0.001). In multivariable logistic regression, independent predictors were renin at T0 (adjusted OR 5.15; 95% CI 1.34-19.78; p = 0.017), PaO₂/FiO₂ ratio (P/F) at T0 (OR 0.02; p = 0.010), and procalcitonin (PCT) at T2 (OR 81.89; p = 0.020). Model discrimination was high (AUC 0.941).

In patients with severe COVID-19-related ARDS, early renin (72 h) is independently associated with 1-year mortality, and serial trajectories provide additional prognostic information. Prospective multicenter validation is warranted.