Is cytomegalovirus infection related to inflammatory bowel disease, especially steroid-resistant inflammatory bowel disease? A meta-analysis.

Background: Human cytomegalovirus (HCMV) infection has been associated with inflammatory bowel disease (IBD). Numerous studies have been conducted to analyze the association between HCMV infection and risk of IBD and steroid-resistant IBD, but no clear consensus had been reached.

Objectives: The aim of this study was to confirm this relationship precisely by doing a systematic review and meta-analysis.

Study design: We identified relevant studies through a search of PubMed and Embase. Studies were eligible for inclusion if they 1) evaluated the association between HCMV infection and IBD disease; 2) evaluated the association between HCMV infection and steroid-resistant IBD disease; 3) were case-control studies or nested case-control studies; 4) provided the numbers (or percentage) of positivity for HCMV infection in cases and controls, respectively. Data were extracted and analyzed independently by two investigators.

Results and conclusion: A total of 18 studies including 1,168 patients and 951 health groups was identified, and HCMV infection was distinctly confirmed as a risk factor for the occurrence and development of IBD. When involving 17 studies including 1,306 IBD patients, a total of 52.9% of patients in the cytomegalovirus (CMV)-positive groups were observed to have steroid resistance, compared with 30.2% of patients in the CMV-negative groups. There was a significant difference in the risk of steroid resistance between people exposed to HCMV infection and those not exposed HCMV infection in IBD patients. This meta-analysis suggested that HCMV infection is associated with an increased risk for IBD and steroid-resistant IBD.