Introduction: Oral tablet bowel preparation containing sodium sulfate, magnesium sulfate and potassium chloride (OST) was developed to improve patient compliance. We previously suggested a relationship between OST and erosive gastritis. Based on our prior findings we hypothesized that the potassium chloride component in OST is responsible for erosive changes and reducing contact time with gastric mucosa will decrease incidence of erosive gastritis. To achieve that we changed OST preparation instructions from dosing over 15-20 minutes as per package insert (OST-P) to one hour allowing 4-5 minutes delay and more water intake between tablets (OST-D).
Methods: We conducted a retrospective review of patients undergoing upper esophagogastroduodenoscopy (EGD) at the time of colonoscopy by a single operator from December 12, 2021, to May 3, 2022. We compared the incidence of erosive gastritis in patients receiving OST-D versus oral sulfate solution (OSS) and PEG. We revised EGD images and classified erosive gastritis into mild (focal superficial erosions), moderate (diffuse superficial erosions), and severe (deep, cratered erosions, with scab). We reviewed EGD images from our prior OST study (OST-P) and classified lesions in the same manner. Exclusion criteria included NSAID use and H. pylori infection.
Results: 135 patients underwent EGD at the time of colonoscopy. 11 excluded due to NSAID use or H. pylori infection and 1 due to unavailable prep data. Of the remaining 123 patients, 41 received OST-D, 82 OSS and PEG. Among 41 OST-D patients reviewed, 24 (58%) had inflammatory changes characterized by erosions and adherent blood compared to 27/33 (82%) with OST-P (p=0.04). Severity in this study was lower with OST-D; severe erosive gastritis was seen in 1/41 (2.4%) moderate in 11/41 (27%) and mild in 12/41 (29%) compared to 4/33 (12%), 14/33 (42%) and 9/33 (27%) respectively with OST-P. Erosive changes were also found in 24/82 (30%) of patients who received OSS and PEG, which is significantly lower than OST- D group 24/41(58%, p < .01).
Discussion: While these findings are consistent with our prior study which suggested an increased incidence of erosive gastritis with OST prep, this study suggests that increasing time interval between tablets leads to a decrease in incidence and severity of erosive gastritis suggesting that erosive changes are related to retention of OST tablets. Endoscopists need to be made aware of these findings to decrease incidence and severity of erosive gastritis in patients using OST.
