P233 Cytomegalovirus colitis in patients with moderate-to-severe Ulcerative Colitis: diagnosis, clinical impact and treatment efficacy

Cytomegalovirus (CMV) colitis is a serious concern worsening the prognosis of patients with ulcerative colitis (UC), involving mainly those who are not responding to immunosuppressive therapy. CMV colitis is an independent predictor of hospitalisation and surgery. Diagnosis of CMV colitis can be obtained either via immunohistochemistry (ICH) or tissue polymerase chain reaction (PCR), possibly both. We aimed to assess the prognostic impact of CMV colitis in patients with UC and the clinical utility of testing for CMV plasma-DNA reactivation. We conducted a retrospective, observational, monocentric study in our IBD center in Bologna. Consecutive patients hospitalized for moderate-to-severe ulcerative colitis from January 2020 to June 2023 were included. Patients were tested for CMV colitis at hospitalization, along with other concomitant infections. Diagnosis of CMV-colitis was made either by ICH on colonic mucosa histological samples or on resected colon specimens. Need of surgery was evaluated at 28, 180 and 365 days. Basal characteristics of patients according to the presence or absence of CMV organ disease were compared with Mann-Whitney, X2 or Fischer tests, as appropriate. A Kaplan-Meier survival analysis was calculated to verify whether antiviral treatment for CMV organ disease had an impact on avoiding surgery. A total of 135 patients were included. CMV organ disease was present in 37 (27.4%). Around half (51.4%) were diagnosed endoscopically, and 62.2% had evidence of plasma reactivation with a median of 1008 cp/mL CMV-DNA viral load (IQR 318-2980). Differences between the two groups (CMV colitis vs non CMV) included age (p = 0.004), Charlson Comorbidity Index (CCI) (p = 0.003), refractory disease (p = 0.007), and median CMV-DNA viral load (p < 0.001). Patients with CMV colitis needed surgery in 24/37 cases within 1 year from the diagnosis, compared to 41/98 in the non-CMV group. Interestingly, among the first group, 54% of cases underwent colectomy within 28 days, whereas only 34.1% underwent colectomy in the non-CMV group (p = 0.049). At multivariable analysis, steroid refractory disease, CCI and serum CMV-DNA reactivation were associated with CMV colitis. The latter had the highest OR (17.7 p < 0.001). Kaplan-Meier showed that patients who were treated with anti-viral therapy had a significant reduction of the risk of receive surgical treatment (p<0.001) [Table 1]. CMV-DNA plasma reactivation is independently associated to CMV colitis. The use of anti-viral treatment is able to reduce the risk to underwent surgery, suggesting that screening of CMV colitis is mandatory in patients with moderate-to-severe UC.