Predictive Value of the Red Cell Distribution Width to Albumin Ratio For Hospitalization due to Inflammatory Bowel Disease Flares

Author(s): Kumari Priya Yadav, Scott Golden, Zaid Sameer Jaber Weher, Pramita Prem, Vipin Gupta, Mayuri Gupta

Background: Hospitalizations for inflammatory bowel disease (IBD) flares remain common despite advances in biologic therapy and outpatient monitoring. Clinicians still lack simple, low-cost tools that identify patients at imminent risk for severe flare before clinical deterioration occurs.

Objective: To evaluate whether the red cell distribution width to albumin ratio (RAR), a composite biomarker derived from routine laboratory testing, predicts hospitalization for IBD flare when measured weeks to months prior to presentation.

Methods: We performed a retrospective cohort study of adults with ulcerative colitis (UC) or Crohn’s disease (CD) admitted between 2021 and 2023. The most recent outpatient or emergency department RDW (%) and serum albumin (g/dL) obtained within three months prior to admission were used to calculate RAR. The primary predictor was RAR ≥4.3. The primary outcome was hospitalization for IBD flare confirmed by detailed chart review.

Results: Among 41 patients (mean age 47.9 ± 18.8 years; 46.3% female), 22 (53.7%) were hospitalized for IBD flare. Mean RAR was 4.57 ± 1.93, and 16 patients had RAR ≥4.3. Elevated RAR was strongly associated with flare related hospitalization (OR 9.9, 95% CI 1.52–64.24; p=0.01). Other demographic and behavioral variables were not significantly associated with hospitalization.

Conclusion: An elevated RDW to albumin ratio measured up to three months prior to presentation was strongly associated with hospitalization for IBD flare. RAR represents a pragmatic, low-cost biomarker that may enable earlier outpatient intervention and offers a promising foundation for prospective, biomarker-guided flare prevention strategies.