Histopathologic Patterns of Colitis in Patients with Impaired Renal Function

Objectives: To characterize the histopathologic features of colitis in patients with impaired renal function. Methods: We retrospectively identified 413 patients who underwent colonoscopic evaluation for colitis between 2011 and 2015. Patients were divided into four groups based on estimated glomerular filtrate rates. Patients with impaired renal function were compared to overall and age-matched patients with normal renal function. Results: Compared to a preponderance of inflammatory bowel disease (33%) and lymphocytic colitis (9.6%) in patients with normal renal function, ischemic colitis (58%) was the predominant histopathologic pattern in the patients with impaired renal function. Infectious colitis was the second most common pattern (20.8%), with Clostridium difficile and cytomegalovirus infections being more frequent. Medication-induced injury was the third most common pattern, with crystal-associated injury being the exclusive pattern found in this study. Conclusions: Colitis in patients with impaired renal function is etiologically distinct from that seen in patients with normal renal function.