Cytomegalovirus infection and steroid-refractory inflammatory bowel disease: possible relationship from an updated meta-analysis.

Aims: Many studies have suggested Cytomegalovirus infection might be implicated in steroid-refractory inflammatory bowel disease (IBD), in which situation management is extremely difficult. CMV infection being a potential cause of IBD have drawn great attention of clinicians, with insufficient evidence to reach conclusions.
Methods: We conduct this meta-analysis to explore the association of CMV infection and steroid-refractory IBD by collecting relevant articles. Literature collections were conducted by searching PubMed, EMBASE, and the cochrane library databases. Pooled risk ratios (RR) with corresponding 95% confidence intervals (CIs) were calculated to estimate the strength of the link between CMV infection and steroid resistance in IBD using Stata 12.0.
Results: Thirteen eligible studies with a total of 1119 patients conducted in eight countries were included. The steroid resistance rate in the CMV (+) groups was 62.8%, while that in the CMV (-) groups was 29.2%. The pooled RR of steroid resistance rate in CMV (+) groups compared to CMV (-) groups was 2.343 (95% CI 1.715-3.202, P = 0.0000). Due to marginal heterogeneity across studies (I ²  = 77.6%), the random effects model was used. Subgroup analysis based on geographic differences did not alter the overall positive association between CMV infection and steroid resistance in IBD. There is no significant publication bias observed based on the funnel plot and Begg's test.
Conclusions: This meta-analysis disclosed 2.34 fold increased risk of progressing into steroid-refractory IBD in CMV (+) group compared with the CMV (-) group, indicating that CMV infection might be a plausible cause of steroid-refractory IBD.