#1119 Iodine contrast does not contribute to impaired kidney function or need for dialysis
Authors: Westerlund Magnus , Mörtberg Lina Josefin Gisela 
Published: May 2024

Abstract

Background and Aims
Imaging diagnostics play a crucial role in the management of patients with acute and critical conditions or suspected underlying disease like infections or malignancy. These examinations are often enhanced by intravenous iodine-based contrast, to improve the imaging quality and the diagnostic accuracy.
For long, there has been a conception that these contrast materials are nephrotoxic, but the last decade has provided a significant quantity of modern studies suggesting that this is not the case.
The present study evaluates if earlier contrast exposure has contributed to progress in CKD and the need of initiating dialysis treatment in patients who were in maintenance dialysis treatment at the Västerås hospital at the time of inclusion.

Method
All patients admitted to the dialysis ward in Västerås the 1st of January 2022 were included and copies of all radiology surveys and all lab values from the electronical records for this study population for the last 10 years were extracted to check for contrast exposure. For some patients, this occurred when they were already on maintenance dialysis treatment, others were pre-dialytic at the time or had not yet developed any kidney impairment.
For every contrast exposure, we checked the previous creatinine and the earliest creatinine after the examination to check for acute kidney injury, AKI, as defined by KDIGO.
As a secondary outcome, we investigated the frequency of examinations where contrast otherwise would be indicated, but was withhold, due to fear of contrast induced AKI.

Results
In total, 83 patients were included in this study, and among them there were 121 cases of contrast exposure. There were no events of AKI when eGFR was &gt; 30 ml/min. In the subgroup of patients with eGFR &lt; 30 ml/min, but not in dialysis at the time of the examination, there were only 25 cases of contrast exposure, and only one event of AKI, but this was considered largely due to overhydration and decompensated heart failure and resolved with proper treatment. Among the patients already in dialysis, there were 65 contrast exposures, and no event where any subjects lost their residual kidney function due to contrast induced AKI.
In the meantime, there were 249 examinations where contrast material was withheld due to low eGFR, even though it normally would be indicated by the reason of the examination.

Conclusion
There was none significant event of potential contrast induced AKI among the patients in our study and no patient had any lasting impact on their kidney function from contrast exposure. Contrast exposure does not seem to be a common contributing cause of progressing to end stage renal disease.
This is well in line with previous, modern observation studies, suggesting that the risk of contrast induced nephropathy is overrated or possible even a myth.
Perhaps even more importantly, contrast enhancement was often inadequately withheld, even though it normally would be necessary to accurately make the diagnosis that was the purpose of ordering the study. Poor imaging quality limits the ability to make correct diagnoses, resulting in substandard treatment for the CKD-population.