Outcomes Associated With Continuous Renal Replacement Therapy in Acute Respiratory Distress Syndrome With Acute Kidney Injury: A National Inpatient Sample Analysis.

Background Acute respiratory distress syndrome (ARDS) is frequently complicated by acute kidney injury (AKI) and is associated with adverse outcomes. Continuous renal replacement therapy (CRRT) is commonly used in critically ill patients with hemodynamic instability; however, nationally representative data evaluating outcomes associated with CRRT use in ARDS complicated by AKI are limited. Materials and methods We conducted a retrospective cohort study using the Healthcare Cost and Utilization Project National Inpatient Sample (HCUP-NIS) from 2016 to 2021. Adult hospitalizations with ARDS and AKI were identified using ICD-10-CM codes. Patients with end-stage renal disease were excluded. Multivariable logistic regression analyses were performed to evaluate the association between CRRT use and in-hospital outcomes, adjusting for demographics, comorbidities, hospital characteristics, and primary payer. Discharge weights were applied to generate nationally representative estimates. Results Among an estimated 485,035 hospitalizations with ARDS and AKI, 26,995 (5.6%) patients received CRRT. Unadjusted in-hospital mortality was significantly higher among patients receiving CRRT compared with those not receiving CRRT (77.7% vs. 43.1%, p < 0.001). After multivariable adjustment, CRRT use remained associated with higher odds of in-hospital mortality (adjusted odds ratio [aOR] 3.30; 95% CI 3.06-3.55) and higher odds of mechanical ventilation, cardiac arrest, sepsis, vasopressor use, disseminated intravascular coagulation, extracorporeal membrane oxygenation use, and arrhythmia (all p < 0.001). Conclusions Because patients requiring CRRT likely represent those with greater illness severity and because physiologic severity measures (e.g., Sequential Organ Failure Assessment [SOFA] and Acute Physiology and Chronic Health Evaluation [APACHE] scores) are unavailable in the HCUP-NIS, these associations should be interpreted cautiously and likely reflect confounding by indication and residual confounding rather than a direct causal effect of CRRT. CRRT use was associated with substantially higher in-hospital mortality, complication burden, and healthcare resource utilization, identifying a subgroup of patients with severe multisystem organ failure and poor short-term prognosis.