Renin does not associate with mortality or AKI in acute respiratory distress syndrome

Background: Renin may be a marker of severity of illness and mortality in critically ill patients. Angiotensin II infusions in patients with lower renin levels may increase the rate of renal recovery from dialysis-requiring AKI. Given that most ACE is found in the lungs and an ACE defect would lead to higher renin levels, we tested associations between renin and clinical outcomes in patients with acute respiratory distress syndrome (ARDS). Methods: We studied 63 patients with plasma renin measurements enrolled in a phase 1/2 trial of bone marrow-derived human MSCs for moderate-severe ARDS. We estimated associations between renin levels (as a continuous variable) and ARDS severity (assessed by PaO2/FiO2), mean arterial pressure (MAP), and serum creatinine at randomization. We then examined if renin was associated with subsequent AKI (defined as ≥ 2x ↑ SCr or new dialysis) or in-hospital mortality. Results: The median renin was 72 pg/mL (25th-75th percentile 33-181 pg/mL). At randomization, there was no cross-sectional correlation between renin level and PaO2/ FiO2 (R2 = 0.03, 95% CI 0.00-0.14, p = 0.21), between renin level and MAP (R2 = 0.01, 95% CI 0.00-0.12, p = 0.35), or between renin level and serum creatinine (R2 = 0.003, 95% CI 0.00-0.08, p = 0.68). In longitudinal unadjusted analysis, renin did not significantly associate with AKI (OR 1.006 per 10 pg/mL increase, 95% CI 0.992-1.021, p = 0.41) or 28-day mortality (OR 1.000 per 10 pg/mL, 95% CI 0.987-1.014, p = 0.97). Results were similar in adjusted analyses. Serum creatinine at randomization was associated with AKI (OR 3.27 per mg/dL, 95% CI 1.47-7.30, p = 0.004). Conclusions: We did not find that renin level is a risk factor for mortality or AKI in moderate-severe ARDS. (Table Presented).