Introduction: Up to 67% of critically ill patients develop acute kidney injury during their hospitalization. Patients with hemodynamic instability often cannot tolerate standard hemodialysis due to abrupt volume shifts and instead require continuous renal replacement therapy(CRRT). CRRT is advantageous as it can facilitate correction of acidosis, electrolyte derangements, and remove volume. Previous studies have explored the optimal timing of initiation, the specific modality, and the use of anticoagulation during CRRT. However, there are few studies evaluating the prognosis of prolonged CRRT. This study’s aim is to determine if prolonged duration of CRRT increases the risk of mortality in critically ill patients.
Methods: We conducted a retrospective cohort study of adult patients admitted to an intensive care unit (ICU) at a major academic teaching hospital between 2016 and 2023 who underwent CRRT. A multivariate logistic regression analysis was performed to investigate potential associations between the duration of CRRT and mortality rates as well as renal recovery at discharge. The duration of CRRT was categorized into quintiles, with the shortest duration group (less than 0.5 days) designated as the reference group for comparison.
Results: There were 1,256 patients included in the study. The duration of CRRT ranged from 0 to 27 days, with a median of 1.7 days (IQR: 0.7–3.7 days. The predictors of mortality were age (OR 1.03, p< 0.001), pre-existing renal disease (OR 0.52, p< 0.001), and pre-existing end-stage renal disease (OR 0.73, p=0.046). CRRT duration was also a predictor of mortality: patients undergoing prolonged CRRT for more than 5 days were associated with improved mortality when compared to the reference group (OR 0.35, CI 0.22-0.55, p< 0.001), indicating that the highest risk of mortality was within the first 12 hours of CRRT initiation. In total, we observed 789 (62.9%) mortalities, and of the 465 patients who survived, 401 (86.2%) were not dialysis-dependent at the time of discharge.
Conclusions: Prolonged CRRT does not increase risk of inpatient mortality, and those who survived had high chance of renal recovery. Our study demonstrated that prolonged CRRT is not futile and decisions about duration of CRRT should be tailored to the individual patient.
