Bridging the Gap Between Endoscopy and Histology Indices: A Multi-Index Comparison in 146 Ulcerative Colitis Patients

Background Ulcerative Colitis (UC) is a chronic inflammatory bowel disease affecting the colonic mucosa, with a relapsing-remitting course. Disease activity is assessed using clinical, serologic, endoscopic, and histological parameters, among which the latter two remain the cornerstone for assessing disease severity and therapeutic response. However, limited studies have evaluated the correlation between endoscopic and histological activity. This study evaluates the correlation between the Mayo endoscopic score (MES) and validated histological indices, namely the Geboes score (GS), Nancy index (NI), and Robarts histological index (RHI), to determine the most practical and reliable histological scoring system. Methods This cross-sectional study was conducted over a period of two and a half years at a tertiary care hospital in North India and included 146 established UC patients. Colonoscopic evaluation was performed by a single gastroenterologist, and biopsies were obtained from areas showing the highest possible MES. Subsequent histopathological examination and scoring using the histological indices (GS, NI, and RHI) were performed independently by pathologists masked to the endoscopic findings. Correlations were assessed using the Chi-Square test and Spearman's rho to evaluate relationships between endoscopic and histopathological scores. Results A total of 146 biopsies were analyzed, with a median patient age of 34 years; male patients constituted 56% of patients, and the recto-sigmoid region was the most commonly affected site (62%). Moderate (50%) and severe (32%) endoscopic aspects suggestive of UC activity were predominant. Correlation coefficients between MES and GS/RHI/NI were moderate (rho = .617/.622/.599, respectively; P < .001 for all three correlations). The NI was the fastest to evaluate and demonstrated a similar correlation with the MES compared to the GS and RHI. Conclusion A moderate yet consistent correlation was observed between the MES and all three histopathological indices, highlighting their reliability in reflecting disease severity and supporting their interchangeable use in routine practice. Among them, the NI emerged as the most practical and user-friendly scoring system due to its simplicity and rapid applicability, while maintaining diagnostic performance comparable to the GS and RHI.