← Issue №4/ week of Jul 26, 2026/IBD

"The role of red cell distribution width in inflammatory bowel disease evaluation: a comprehensive systematic review and meta-analysis".

From GI Signals issue №4: what this paper found, what it changes, and where it sits against the current standard of care, reviewed by Simon Mathews, MD.

IBD meta analysis · Jul 27, 2026 · BMC Gastro · IF 2.5

"The role of red cell distribution width in inflammatory bowel disease evaluation: a comprehensive systematic review and meta-analysis".

New evidencemeta-analysissystematic reviewbiomarkerCrohn's disease
Clinical takeawayConsider RDW as an adjunctive marker for IBD activity, especially in Crohn's disease, but do not replace CRP or fecal calprotectin with RDW alone. RDW's utility in UC remains less clear.
What it foundRDW >14% differentiates active Crohn's disease from remission with 86% sensitivity and 78% specificity (AUC 0.83). RDW levels were also significantly higher in active Crohn's disease compared to active ulcerative colitis (MD = 0.59, p < 0.005).
ContextConfirms RDW's association with IBD activity but does not establish superiority over existing markers like CRP or fecal calprotectin. RDW's role in UC requires further investigation.
Refinessuggested applicable standard· ACG Clinical Guideline Update: Ulcerative Colitis in Adults, Am J Gastroenterol 2025;120(6):1187-1224; AGA Living Guideline on Pharmacological Management of Moderate-to-Severe UC, Gastroenterology 2024 (panel review March 2026, no changes)

Decision at stakeusing biomarkers to assess disease activity in ulcerative colitis

Confirm ulcerative colitis with endoscopy showing continuous colonic inflammation from the rectum plus histology, after excluding infection with two-step CDI testing.

From our summary of this standard, unedited — the part the paper bears on. marks omitted text. Our wording, not the guideline's; read the source for its own text.

Our full summary of this standard

Confirm ulcerative colitis with endoscopy showing continuous colonic inflammation from the rectum plus histology, after excluding infection with two-step CDI testing. Treat mild-moderate disease with 5-ASA by route and extent (suppository for proctitis, enema for left-sided, oral plus rectal for extensive); if 5-ASA fails, treat as moderate-to-severe rather than stepping up gradually. Position advanced therapy by EFFICACY TIER, not by an anti-TNF-first rule. Advanced-therapy-naive, higher efficacy: infliximab, vedolizumab, ozanimod, etrasimod, upadacitinib, risankizumab, guselkumab; intermediate: golimumab, ustekinumab, tofacitinib, filgotinib, mirikizumab; lower: adalimumab. PREVIOUSLY TNF-EXPOSED, higher efficacy: tofacitinib, upadacitinib, ustekinumab; lower: adalimumab, vedolizumab, ozanimod, etrasimod - S1P modulators are weakest in exactly this group. Do not cycle within the anti-TNF class after primary non-response; switch mechanism. Apply treat-to-target (STRIDE-II) to endoscopic improvement (MES 0-1). Screen for acute severe UC by Truelove-Witts and admit for IV steroids. Begin CRC surveillance 8-10 years after DIAGNOSIS for extensive or left-sided disease; isolated proctitis follows average-risk screening.

ACG Clinical Guideline Update: Ulcerative Colitis in Adults, Am J Gastroenterol 2025;120(6):1187-1224; AGA Living Guideline on Pharmacological Management of Moderate-to-Severe UC, Gastroenterology 2024 (panel review March 2026, no changes) ↗
Khalil Y … Abdelsamad A · BMC Gastroenterology · IF 2.5 · PubMed ↗Permalink
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