Abstract Background Idiopathic chronic ulcerative colitis (UC) is an inflammatory bowel disease (IBD) characterized by continuous inflammation of the colonic mucosa, extending proximally from the rectum. Accurate evaluation of inflammatory activity is essential to guide treatment, but it requires integrating multiple dimensions: clinical symptoms, inflammatory biomarkers, endoscopic findings, and histopathological changes. However, these parameters do not always correlate with each other, which can complicate objective disease assessment. In clinical practice, fecal calprotectin and C-reactive protein are widely used as indirect markers of inflammation, although their degree of correlation with endoscopic and histological activity remains variable. Methods Observational, cross-sectional, and analytical study conducted between March 2023 and June 2025 at the IBD Clinic of the Hospital General de México “Dr. Eduardo Liceaga”. A total of 218 patients with confirmed UC diagnosis were included. Clinical variables (Truelove and Witts scale), biochemical variables (CRP and fecal calprotectin), endoscopic variables (Mayo scale), and histological variables (Riley index) were collected. The Spearman correlation coefficient was applied, considering statistical significance with p 0.05. Results A total of 218 patients were included; 51.4% were women, and the mean age was 42.3 ± 14.5 years. Pancolitis (E3) was present in 65.6%, and 40.8% received advanced therapy. The most frequent extraintestinal manifestations were arthralgias (29.4%). CRP showed a low to moderate positive correlation with fecal calprotectin (ρ = 0.349, p 0.001) and a weak correlation with Truelove and Witts (ρ = 0.265, p 0.001), with no association with the Mayo scale (ρ = 0.081, p = 0.236) or Riley index (ρ = 0.045, p = 0.504). Fecalcal protectin showed no significant correlation with Truelove and Witts (ρ = 0.030,p = 0.660) or Mayo (ρ = –0.115, p = 0.089). The Riley index showed a low to moderate positive correlation with the Mayo scale (ρ = 0.299, p 0.001). No significant correlations were observed between the Truelove and Witts scale and Mayo (ρ = 0.039, p = 0.569) or with the Riley index (ρ = 0.001, p = 0.990). Table 1 describes the clinical, biochemical, endoscopic, and histological characteristics of the evaluated patients. Conclusion In this cohort, endoscopic and histological parameters showed asignificant correlation, while serum and fecal biomarkers and clinical scales showed limited correlations. These findings reinforce the importance of integrating multiple domains to more accurately assess inflammatory activity in UC. Conflict of interest: Rodriguez Cruz, Hector: No conflict of interest Hernandez Antolin, Victor: No conflict of interest Gonzalez Lopez, Roberto Emmanuel: No conflict of interest Rosales Tellez, Paola: No conflict of interest Chida Romero, Jesus Antonio: No conflict of interest Cabrera Palma, Guillermo: No conflict of interest Dolores Bravo, María del Carmen: No conflict of interest Bustillos García, Fatima Julissa: No conflict of interest Martinez Vega, Melanie Verónica: No conflict of interest Contreras Aviles, Estefania: No conflict of interest Sebastian Ocampo, Valeria Natalie: No conflict of interest Lopez Perez, Raquel Yazmin: No conflict of interest Jimenez Bobadilla, Billy: No conflict of interest 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.
Cruz et al. (Thu,) studied this question.