The cumulative colectomy rate in patients with cytomegalovirus-positive ulcerative colitis.

To the Editor:

With great interest, we read the article titled “Long-term outcomes of cytomegalovirus reactivation in patients with moderate to severe ulcerative colitis: a multicenter study” by Kim et al.1 In this very-well designed study, authors have found that the cumulative colectomy rate was significantly higher in the cytomegalovirus (CMV)-positive group than in the CMV-negative group. They concluded that the patients who had CMV-reactivated ulcerative colitis (UC) showed poor outcomes at the long-term follow-up, and the long-term efficacy of ganciclovir therapy was marginal. These findings provided important information regarding the association between UC and CMV infection. However, we have some suggestions regarding methodology of the study.

In the study, CMV IgM antibody or histologic detection of inclusion bodies on hematoxylin and eosin (H&E)-stained sections, positive immunohistochemical staining, or CMV DNA amplification by polymerase chain reaction (PCR) tests were used to detect CMV infection, but some data seems to be missing. We think which method was chosen for which patient and significant differences between groups should be emphasized if there is any. We know that sensitivity and specificity of tests that detect the virus differ from each other. For instance, the specificity and sensitivity values of DNA PCR is 66% and 100%, respectively, while for H&E, it is 92%–100% and 10%–87%.2 This may lead to different results in the comparison between groups. Moreover, patients who dropped out were included in results of the study. We think, these patients should be excluded because there was no information regarding follow-up data of these patients. Authors postulated that these 11 patients might have a good clinical course; they would have visited a participating center if the patients experienced a flare-up. However, these 11 patients may be admitted due to flare up apart from 10 participating centers since there is no feedback information.

In addition, authors reported that three patients showed evidence of CMV reactivation during the follow-up period in CMV-negative group and those patients were successfully treated with ganciclovir. However, this study has no information regarding the outcome of those patients. It seems like these patients had sustained remission. Moreover, we suggest that patients with CMV reactivation in CMV-negative group should be added to CMV-positive group because the complications which occurred after CMV diagnosis may be associated with viral reactivation. If these patients are included in CMV-positive group, cumulative colectomy rate will change.

Consequently, we conclude that, before making certain interpretations, this work should be rearranged in light of the above mentioned suggestions. This could provide the readers of the journal clearer information regarding the role of CMV infection in cumulative colectomy rate and the clinical course of the UC.