Hydration Unnecessary to Prevent Contrast-Enhanced Nephropathy

Nancy A. Melville

February 19, 2020

The common practice of hydration with sodium bicarbonate prior to contrast-enhanced CT imaging shows no benefit in terms of renal safety compared to withholding hydration in patients with stage 3 chronic kidney disease (CKD), new research shows.

"To our knowledge, our study is the first that directly compares no prehydration with sodium bicarbonate prehydration prior to nonemergency contrast-enhanced CT with intravenous iodine-based contrast media administration," the authors of the new Kompas trial report.

"Based on these results, we believe that our study provides sufficient evidence that preventive hydration can be withheld in this population."

Although acute kidney injury (AKI) following the administration of iodine-based contrast media with CT imaging is known to generally be mild and without long-term effects, international guidelines still call for preventive hydration, with sodium bicarbonate or isotonic saline, for high-risk patients.

Few studies, however, have evaluated the efficacy and safety of hydration prophylaxis compared with no hydration.

No Difference in Outcomes, Fewer Costs, With No Prehydration

For the multicenter Kompas trial, published online February 17 in JAMA Internal Medicine, Rohit J. Timal, MD, and colleagues enrolled 523 patients with stage 3 CKD at six hospitals in the Netherlands.

Patients were randomized 1:1 to receive prehydration with 250 mL of 1.4% sodium bicarbonate or no hydration prior to undergoing elective contrast-enhanced CT between April 2013 and September 2016.

Patients were a median age of 74 and 64.2% were male.

For the primary endpoint of mean relative increase in serum creatinine level 2-5 days following contrast administration, the mean increase in the prehydration group, compared with baseline, was 3.5% (SD, 10.3) versus 3.0% (SD, 10.5) in the no prehydration group (mean difference, 0.5%; 95% CI, −1.3 to 2.3; P < .001 for noninferiority).

Furthermore, there were no significant differences in the secondary outcomes of post-contrast AKI, which occurred in 1.5% (4 of 261) of patients in the prehydration group and 2.7% (7 of 262) of the no prehydration group (P = .36).

The predefined subgroup analysis also showed no significant differences.

There were no reports of acute heart failure, and none of the patients required dialysis.

Importantly, the withholding of hydration also reduced costs, with hydration costing on average $144 per patient, compared with no cost if prophylaxis was withheld, note Timal, of the Department of Cardiology, Leiden University Medical Center, the Netherlands, and coauthors.

"Omission of prophylactic measures did not lead to increased healthcare expenses during the 2 months' follow-up," they write.

There are some notable limitations, including the fact that because serum creatinine level was assessed only in patients with CKD undergoing elective CT, the results cannot be extrapolated to angiography with intra-arterial contrast administration or to acute interventions, such as percutaneous transluminal (coronary) interventions.

In addition, for feasibility reasons, the study was powered for a relative increase in serum creatinine level instead of post-contrast AKI, consistent with other studies, the authors note.

"This is a consequence of the noninferiority design and the low risk of post-contrast-AKI in this clinical setting," they explain.

In conclusion, Timal and colleagues write: "Among patients with stage 3 CKD undergoing contrast-enhanced CT, 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."

Of note, a recent joint statement from the American College of Radiology and the National Kidney Foundation asserts that the risk of iodinated contrast-induced AKI in patients with reduced kidney function is in fact "overstated," as reported by Medscape Medical News.

The Kompas study was supported by Stichting Achmea Gezondheidszorg. Disclosures for the other authors are listed in the article.

JAMA Int Med. Published online February 17, 2020. Abstract

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