Immunomodulator medications (IMM) play a vital role in the care of patients with inflammatory bowel disease (IBD). IBD practice guidelines recommend myelosuppression monitoring after initiation of IMM.


To identify adherence rates and predictors of myelosuppression monitoring after IMM initiation in a large practice setting.


We identified a national cohort of VA users with IBD for the fiscal years 2003–2009 using the Veterans Affairs administrative datasets. Subjects with filled prescriptions for IMM were included. The primary endpoint was the proportion of subjects who had a white blood cell (WBC) test completed within 90 days of the IMM index date. Determinants of myelosuppression monitoring were identified by univariate and multivariate analyses.


A total of 6045 unique IBD patients were identified with filled IMM prescriptions. Overall, only 57% of subjects completed a WBC test within 90 days of IMM index date. Monitoring rates increased over time, from 48% in 2003 to 75% in 2009. There was variability of monitoring rates by facility, ranging from 0 to 83%. In multivariate analyses, older age at IMM index date was associated with a lower rate of monitoring. Frequency of VA encounters and IMM index date were associated with increased rates of myelosuppression monitoring.


Monitoring for myelosuppression among veterans with inflammatory bowel disease after immunomodulator medications initiation is low with wide variability based on facility. This may reflect a low quality of care among veterans with IBD. Provider- and system-wide interventions are needed to improve adherence and reduce variability of immunomodulator medications monitoring across facilities.