Patients with ulcerative colitis (UC) are at high risk for cytomegalovirus (CMV) reactivation. The usefulness of the CMV antigenemia assay in active UC patients has rarely been studied. We assessed whether the assay detects CMV colitis and predicts clinical outcomes in patients with UC.

We retrospectively reviewed the medical records of patients hospitalized for moderate-to-severe UC from 2003 to 2012. Positive CMV antigenemia was defined as ≥1 pp65-positive cell per 2×10⁵ polymorphonuclear neutrophils. CMV colitis was defined as the presence of inclusion bodies and/or positive immunohistochemistry in the colonic mucosa. The primary outcome was steroid refractoriness, defined as the absence of clinical improvement after intravenous high-dose steroid administration.

A total of 43 patients were enrolled. CMV antigenemia was detected in 12 (27.9%) patients. Positive CMV antigenemia was significantly associated with CMV colitis ( P =0.001). The sensitivity and specificity of positive CMV antigenemia for diagnosing CMV colitis were 66.7% and 87.1%, respectively. Steroid refractoriness was found in 11 of 12 (91.7%) and 12 of 31 (38.7%) patients with positive and negative CMV antigenemia, respectively ( P =0.002). The independent predictors for steroid refractoriness were positive CMV antigenemia (adjusted odds ratio [OR], 7.73; 95% confidence interval [CI], 1.22-49.19; P =0.030) and a shorter duration from the diagnosis of UC (adjusted OR, 0.99; 95% CI, 0.98-0.99; P =0.025).

The CMV antigenemia assay shows low sensitivity but high specificity for detecting CMV colitis and may predict steroid-refractory UC. Early rescue therapy might be considered in UC patients positive for CMV antigenemia.