Comparison of Bolus and Continuous Hydration Regimens for the Prevention of Contrast-Associated Acute Kidney Injury in the Emergency Department: A Randomized Controlled Noninferiority Trial.

Abstract

Objectives: The optimal rate and duration of isotonic hydration therapy for preventing contrast-associated acute kidney injury (CA-AKI) remain poorly established. As prolonged hydration therapy is impractical due to the urgency of diagnostic imaging and the limited time available for monitoring in the emergency departments (EDs), this study evaluated whether bolus hydration regimens are noninferior to prolonged hydration protocols.

Methods: This single-center, prospective, open-label, randomized controlled, noninferiority trial was conducted at the ED of a training and research hospital between August 10, 2024, and April 26, 2025. 257 patients undergoing contrast-enhanced computed tomography (CT) with baseline creatinine levels above the reference range (1.2 mg/dL in men and 1.1 mg/dL in women) were included. Patients were stratified by age and sex and randomized to bolus or continuous hydration. The bolus group received 500 mL of isotonic fluid within 30 min before the procedure, followed by 500 mL/hour for 2 h postprocedure. The continuous group received 150 mL/hour for 2 h before and 8 h after the procedure. The primary outcome was the development of CA-AKI, defined as an increase in serum creatinine of ≥ 25% or ≥ 0.5 mg/dL at 48-72 h following contrast administration. Secondary outcomes included 30-day all-cause mortality and the need for dialysis.

Results: The two groups were well-matched in terms of demographic, clinical, or biochemical parameters. The mean baseline creatinine was 1.4 ± 0.21 mg/dL, and the eGFR was 45.6 ± 9.8 mL/min/1.73 m². CA-AKI occurred in 1.7% of the continuous group and 4.9% of the bolus group (absolute risk difference 3.2%; 95% CI -1.3% to 7.7%). As the upper confidence interval limit was below the predefined noninferiority margin of 8%, bolus hydration was noninferior to continuous hydration for CA-AKI prevention. No patients required dialysis. Thirty-day all-cause mortality was comparable (7.6% vs. 7.9%; p = 0.928). Significant improvements were observed in urea, creatinine, and eGFR values in both groups at 48-72 h (p < 0.001).

Conclusion: In this single-center noninferiority trial, a bolus hydration regimen was noninferior to a prolonged continuous regimen for preventing CA-AKI in ED patients with moderately impaired baseline renal function. Bolus hydration may offer a practical alternative in time-constrained ED settings; however, multicenter confirmation is warranted before routine adoption. Trial Registration: ClinicalTrials.gov.identifier: NCT07286526.