Pre-existing Chronic Kidney Disease and Mortality in Non-COVID Acute Respiratory Distress Syndrome: A Propensity-Matched Cohort Study

Background Acute respiratory distress syndrome (ARDS) and chronic kidney disease (CKD) are both associated with substantial morbidity and mortality in the intensive care unit (ICU). Previous research in ARDS has evaluated patients with acute kidney injury, a large portion of whom had coronavirus disease 2019 (COVID-19)-related ARDS. The association between pre-existing CKD and outcomes in non-COVID ARDS remains unclear. We hypothesized that pre-existing CKD is associated with increased mortality in non-COVID ARDS. Methods Using the TriNetX Research Network, we conducted a retrospective cohort study comparing mortality in non-COVID ARDS adults, with- versus without- pre-existing CKD. Patients < 18 years and those with current or prior COVID-19 were excluded. ARDS cases requiring mechanical ventilation within 3 days of the index encounter were included. The CKD and non-COVID cohorts were compared using 1:1 propensity score matching (PSM) for age, sex, race/ethnicity, comorbidities, and other risk factors. Mortality at 14, 30, and 120 days was evaluated using risk and hazard ratios with Kaplan-Meier curves and Cox proportional hazards models. Results In matched cohorts, mortality was higher in the CKD cohort at 14, 30, and 120 days (all p < 0.0001). Specifically, 14-day mortality was 35.01% for CKD patients versus 28.22% in the controls (HR 1.29, 95% CI: 1.17–1.43). At 30 days, the mortality risk was 44.22% and 37.10%, respectively (HR 1.26, 95% CI: 1.15–1.37). Likewise, 120-day mortality was 52.64% and 43.59%, respectively (HR 1.29, 95% CI: 1.19–1.40). Conclusion Pre-existing CKD was associated with a higher risk of mortality in non-COVID ARDS patients, supporting its consideration as a prognostic comorbidity for risk stratification.