Mean corpuscular volume values

Mar 17, 2015 - E-Mentoring in IBD | Volume 08 • 2015

Issue 05

Clinical Question

Is it worthwhile to follow the change in mean corpuscular volume (MCV) values in Crohn’s disease (CD) patients on azathioprine?

Editor’s Bottom Line

CD patients treated with azathioprine who achieve a ∆MCV >7 have improved outcomes.


Bouguen G, Sninsky C, Tang KL, et al. Change in erythrocyte mean corpuscular volume during combination therapy with azathioprine and infliximab is associated with mucosal healing: a post hoc analysis from SONIC. Inflamm Bowel Dis. 2015 Mar;21(3):606–14.


SONIC was a randomized controlled trial comparing the efficacy of infliximab and azathioprine combination therapy versus azathioprine monotherapy in 508 CD patients.

This current study examined the relationship between the mean corpuscular volume value (as a surrogate marker of 6-thioquanine nucleotides concentration) and CD outcome. In the post hoc analysis, patient samples from both study arms have been assessed for ∆MCV from baseline to study week 26.

In the infliximab + azathioprine combination therapy group, 75% of patients with ∆MCV >7 had mucosal healing versus 47.1% of patients with ∆MCV <7 (P=0.0172). Furthermore, patients with a ∆MCV >7 were more likely to have an inflximab trough level above 3. In the azathioprine monotherapy group a ∆MCV >7 was associated with steroid-free clinical remission (63.6% vs. 33.3%, P=0.0046).


Study Design: Retrospective analysis
Funding: Janssen Biotech, Inc.
Allocation: n/a
Setting: n/a
Level of Evidence: 2b (Oxford Levels of Evidence)

The summary and conclusion in this issue of E-mentoring in IBD pertains to the manuscript(s) being reviewed, and should be considered in the context of what is already known surrounding the topic and incorporated into practice as deemed appropriate by the individual learner.