Association Between Mucosal Cytomegalovirus DNA Load and Short-Term Clinical Outcomes in Acute Severe Ulcerative Colitis.

Background Whether cytomegalovirus (CMV) infection is a cause or consequence of relapse or therapeutic refractoriness in patients with ulcerative colitis (UC) remains debatable. This study aimed to evaluate the frequency of CMV infection and the association between mucosal CMV DNA load and medical management failure in patients with acute severe ulcerative colitis (ASUC). Methods Consecutive patients with ASUC admitted between May 2023 and November 2024 were included. All patients received intravenous (IV) hydrocortisone and ganciclovir when quantitative CMV DNA real-time polymerase chain reaction (RT-PCR) levels were >250 copies/mg and/or histopathology demonstrated CMV infection. The primary outcome was to determine the frequency of CMV infection and to evaluate the association between quantitative CMV PCR levels from biopsy samples obtained during sigmoidoscopy and the risk of medical management failure (IV steroids ± ganciclovir). The secondary outcome was medical management failure, defined as the need for rescue therapy. Results CMV infection was detected in 70 (64.8%) patients with ASUC (44 by RT-PCR alone, one by inclusion bodies alone, and 25 by both methods). Patients with medical management failure had a significantly higher CMV DNA load than responders (44,990,045.76 copies/mg (0-754,359,454.0) vs. 249,720.95 copies/mg (0-9,729,500.00); p < 0.05) and a higher proportion of CMV DNA titres >250 and >1000 copies/mg (p < 0.05). Eight patients developed toxic megacolon, among whom seven (87.5%) had CMV infection. Overall, 17 (15.7%) of the 108 patients with ASUC experienced medical management failure. Conclusion Higher mucosal CMV DNA load was associated with medical management failure in patients with ASUC. Patients with higher CMV DNA loads also had higher frequencies of rescue therapy, toxic megacolon, and mortality.