Effect of No Prehydration vs Sodium Bicarbonate Prehydration Prior to Contrast-Enhanced Computed Tomography in the Prevention of Postcontrast Acute Kidney Injury in Adults With Chronic Kidney Disease: The Kompas Randomized Clinical Trial

Abstract

Importance: Prevention of postcontrast acute kidney injury in patients with stage 3 chronic kidney disease (CKD) by means of prehydration has been standard care for years. However, evidence for the need for prehydration in this group is limited.

Objective: To assess the renal safety of omitting prophylactic prehydration prior to iodine-based contrast media administration in patients with stage 3 CKD.

Design, setting, and participants: The Kompas trial was a multicenter, noninferiority, randomized clinical trial conducted at 6 hospitals in the Netherlands in which 523 patients with stage 3 CKD were randomized in a 1:1 ratio to receive no prehydration or prehydration with 250 mL of 1.4% sodium bicarbonate administered in a 1-hour infusion before undergoing elective contrast-enhanced computed tomography from April 2013 through September 2016. Final follow-up was completed in September 2017. Data were analyzed from January 2018 to June 2019.

Interventions: In total, 262 patients were allocated to the no prehydration group and 261 were allocated to receive prehydration. Analysis on the primary end point was available in 505 patients (96.6%).

Main outcomes and measures: The primary end point was the mean relative increase in serum creatinine level 2 to 5 days after contrast administration compared with baseline (noninferiority margin of less than 10% increase in serum creatinine level). Secondary outcomes included the incidence of postcontrast acute kidney injury 2 to 5 days after contrast administration, mean relative increase in creatinine level 7 to 14 days after contrast administration, incidences of acute heart failure and renal failure requiring dialysis, and health care costs.

Results: Of 554 patients randomized, 523 were included in the intention-to-treat analysis. The median (interquartile range) age was 74 (67-79) years; 336 (64.2%) were men and 187 (35.8%) were women. The mean (SD) relative increase in creatinine level 2 to 5 days after contrast administration compared with baseline was 3.0% (10.5) in the no prehydration group vs 3.5% (10.3) in the prehydration group (mean difference, 0.5; 95% CI, -1.3 to 2.3; P < .001 for noninferiority). Postcontrast acute kidney injury occurred in 11 patients (2.1%), including 7 of 262 (2.7%) in the no prehydration group and 4 of 261 (1.5%) in the prehydration group, which resulted in a relative risk of 1.7 (95% CI, 0.5-5.9; P = .36). None of the patients required dialysis or developed acute heart failure. Subgroup analyses showed no evidence of statistical interactions between treatment arms and predefined subgroups. Mean hydration costs were €119 (US $143.94) per patient in the prehydration group compared with €0 (US $0) in the no prehydration group (P < .001). Other health care costs were similar.

Conclusions and relevance: Among patients with stage 3 CKD undergoing contrast-enhanced computed tomography, withholding prehydration did not compromise patient safety. The findings of this study support the option of not giving prehydration as a safe and cost-efficient measure.

Trial registration: Netherlands Trial Register Identifier: NTR3764.

Figure 1.. Trial Flowchart

CT indicates computed tomography; eGFR, estimated glomerular filtration rate. ^aNo blood samples obtained at baseline and/or during follow-up 2 to 5 days after contrast-enhanced CT. ^bProtocol violations are summarized in eTable 1 in Supplement 2.

Figure 2.. Subgroup Analyses

A, Effect size estimate for the primary end point in subgroups. Subgroup analyses were performed on the primary outcome of a relative increase in serum creatinine level 2 to 5 days after intravenous contrast administration. Effect size is calculated as the difference in the mean relative increase in serum creatinine level between both randomization groups. Baseline creatinine clearance was calculated using the Modification of Diet in Renal Disease formula. There were no statistically significant interactions in the various subgroups. The dashed line represents the point estimate of the entire study population. The predefined noninferiority margin was 10%. B, Forest plot of the secondary outcome of risk of postcontrast acute kidney injury (PC-AKI). Subgroup analyses were performed on the secondary outcome of risk of PC-AKI 2 to 5 days after contrast administration in subgroups, calculated as relative risk (RR). eGFR indicates estimated glomerular filtration rate; RF, risk factors.