Does 2 L Polyethylene Glycol Plus Ascorbic Acid Increase the Risk of Renal Impairment Compared to 4 L Polyethylene Glycol?

Background: The use of polyethylene glycol (PEG)-based solutions is the gold standard for bowel preparation. However, PEG use might be associated with the risk of acute kidney injury.
Aims: We aimed to compare the safety of 2 L PEG plus ascorbic acid (AA) versus 4 L PEG.
Methods: Health examinees that underwent colonoscopy and blood tests on the same day at our center were included in this retrospective study. All subjects were prescribed either 2 L PEG plus AA or 4 L PEG for the bowel preparation prior to the colonoscopy. The incidences of electrolyte imbalance and renal impairment after colonic preparation were investigated. Renal impairment was determined if the subject's estimated glomerular filtration rate was measured less than 60 mL/min/1.73 m ² .
Results: Of the 29,789 cases, 14,790 received 2 L PEG plus AA (group A) and 14,999 received 4 L PEG (group B) for colonic preparation. Renal impairment occurred more commonly in group A (n = 467, 3.2 %) than in group B (n = 189, 1.3 %). Electrolyte changes such as hypernatremia and hyperkalemia were more common in group A than group B, whereas hyponatremia, hypokalemia, and hypophosphatemia were more common in group B than group A. Old age, male sex, and the use of 2 L PEG plus AA were independent risk factors for renal impairment.
Conclusions: The evidence strongly suggests that acute kidney injury is more likely to occur when 2 L PEG plus AA is used for the bowel preparation than when 4 L PEG is used.
Clinical Trial Registration Number: KCT0001703.