Abstract Background Assessment of disease activity in ulcerative colitis (UC) relies mainly on endoscopic and histological evaluation, which, although accurate, are invasive, costly, and not always feasible in routine practice. The Fibrinogen-to-Lymphocyte Ratio (FLR) has emerged as a potential non-invasive inflammatory biomarker. Evidence regarding its correlation with UC activity remains limited. Methods A cross-sectional observational study was conducted at the Inflammatory Bowel Disease Clinic of the General Hospital of México. Patients with UC confirmed by clinical, biochemical, endoscopic, and histological criteria were included. Clinical activity was assessed using Truelove–Witts, endoscopic activity using the Mayo endoscopic subscore, and histological activity using the Riley score. FLR was obtained from routine laboratory measurements. Statistical analyses included t-test, Mann–Whitney U, ANOVA, Kruskal–Wallis, Chi-square, and Fisher’s exact test. ROC analysis was used to identify an optimal FLRcutoff predicting moderate–severe activity. Results Sixty-two patients were included (64.5% female; mean age 41.16 ± 12.99 years; mean disease duration 6.74 years). Clinically, 79% were inactive, 19% mild, and 1.6% moderate–severe. Extensive colitis was present in 51.6% (Montreal classification). According to the Mayo endoscopic score, 45.16% had moderate and 20.9% severe activity. Histologically, 40.3% showed mild, 30.64% moderate, and 14.5% severe activity. FLR showed no significant correlation with clinical activity. However, it was significantly associated with moderate–severe endoscopic activity (p = 0.03) and with histological activity (p = 0.02). ROC analysis identified FLI 198 as predictive of moderate–severe histological activity (AUC 0.807), with a sensitivity of 75% and a specificity of 87.5%. Conclusion The Fibrinogen-to-Lymphocyte Ratio is a promising non-invasive biomarker for predicting moderate–severe activity in ulcerative colitis. Its strong association with endoscopic and histological inflammation, combined with low cost and easy availability, suggests a potential role as a complementary tool for disease monitoring. Prospective studies are needed to validate these findings. Conflict of interest: Chida Romero, Jesús Antonio: No conflict of interest González López, Roberto Emmanue: No conflict of interest Rosales Tellez, Paola: No conflict of interest Rodriguez Cruz, Hector: No conflict of interest Sebastián Ocampo, Valeria Natalie: No conflict of interest Hernández Antolin, Víctor: No conflict of interest Contreras Aviles, Estefania: No conflict of interest Jiménez Bobadilla, Billy: No conflict of interest López Pérez, Raquel Yazmin: No conflict of interest Cabrera Palma, Guillermo: No conflict of interest Dr. De Leon Rendon, Jorge Luis: Dr. Jorge Luis De León Rendón is a member of Advisory Boards, key opinion leader, and speaker for Abbvie Mexico, Takeda Mexico, and Janssen Mexico. He has served as a key opinion leader and lecturer for Schwabe Pharma Mexico, Servier, Pfizer, Alfasigma, and Siegfried Rhein Mexico. He has received support for research manuscript publication and editing from Takeda and Schwabe Pharma Mexico. Additionally, he has coordinated research studies and medical education programs with Shire, Bristol Myers Squibb, Takeda, Schwabe Pharma, Abbvie, Janssen, MSD, and Roche.
Romero et al. (Thu,) studied this question.
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