Monocytosis Is a Biomarker of Severity in Inflammatory Bowel Disease: Analysis of a 6-Year Prospective Natural History Registry

Inflamm Bowel Dis. 2021 Mar 9;izab031. doi: 10.1093/ibd/izab031. Online ahead of print.

Alyce Anderson 1, Cynthia Cherfane 2, Benjamin Click 3, Claudia Ramos-Rivers 4, Ioannis E Koutroubakis 4, Jana G Hashash 4 5, Dmitriy Babichenko 6, Gong Tang 7, Michael Dunn 4, Arthur Barrie 4, Siobhan Proksell 4, Jeffrey Dueker 4, Elyse Johnston 4, Marc Schwartz 4, David G Binion 4


Author information

  • 1University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
  • 2Division of Gastroenterology, Washington University School of Medicine, St. Louis, Missouri, USA.
  • 3Department of Gastroenterology, Hepatology and Nutrition, Cleveland Clinic, Cleveland, Ohio, USA.
  • 4Division of Gastroenterology, Hepatology and Nutrition, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
  • 5Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos-Jbeil, Lebanon.
  • 6School of Information Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
  • 7School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.


Background: Inflammatory bowel disease (IBD) is associated with alterations of the innate and adaptive immune systems. Monocytes respond to inflammation and infection, yet the relationship between monocytosis and IBD severity is not fully understood. We aimed to characterize the prevalence of monocytosis in IBD and the association between monocytosis and disease severity and IBD-related health care utilization.

Methods: We used a multiyear, prospectively collected natural history registry to compare patients with IBD with monocytosis to those without monocytosis, among all patients and by disease type.

Results: A total of 1290 patients with IBD (64.1% with Crohn disease; 35.9% with ulcerative colitis) were included (mean age 46.4 years; 52.6% female). Monocytosis was found in 399 (30.9%) of patients with IBD (29.3% with Crohn disease; 33.9% with ulcerative colitis). Monocytosis was significantly associated with abnormal C-reactive protein level and erythrocyte sedimentation rate, anemia, worse quality of life, active disease, and increased exposure to biologics (all P < 0.001). Compared with patients without monocytosis, patients with monocytosis had a 3-fold increase in annual financial health care charges (median: $127,013 vs. $32,925, P < 0.001) and an increased likelihood of hospitalization (adjusted odds ratio [AOR], 4.5; P < 0.001), IBD-related surgery (AOR, 1.9; P = 0.002), and emergency department (ED) use (AOR, 2.8; P < 0.001). Patients with monocytosis had a shorter time to surgery, hospitalization, and ED visit after stratifying by disease activity (all P < 0.05).

Conclusions: Patients with IBD with monocytosis, regardless of disease type, are at increased risk for worse clinical outcomes, hospitalization, surgery, and ED use. Peripheral monocytosis may represent a routinely available biomarker of a distinct subgroup with severe disease.

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