Clinical Significance of histologic healing in IBD: Evidence from randomized controlled trials (RCT) and real world (RW) data.

Histologic mucosal healing (HMH) has emerged as a crucial target in managing inflammatory bowel disease, complementing the established goal of endoscopic mucosal healing. This review evaluates the significance of HMH in both Crohn's disease (CD) and ulcerative colitis (UC). In UC, strong evidence shows that HMH correlates with improved long-term outcomes, including reduced hospitalization rates, and decreased need for corticosteroids and colectomy. Histologic healing is increasingly being incorporated as an endpoint in RCTs. Small-molecule therapies, such as S1P modulators and Jak inhibitors, have demonstrated particular efficacy in achieving HMH in UC. Real-world evidence (RWE) further supports HMH's utility as a predictive marker for favorable clinical outcomes in UC. In CD, however, HMH's role is less clear, given challenges in assessing and standardizing histologic healing. RCTs, such as SERENITY and VIVID, show that advanced therapies can achieve HMH in CD, though inconsistent histologic scoring and remission criteria complicate conclusions. Some studies suggest that histologic remission at induction may predict sustained remission, but real-world data offer mixed results regarding its prognostic value. This review provides an overview of current literature, emphasizing the need for standardized histologic assessment and extended studies, particularly for CD, while affirming HMH's growing importance in achieving deeper remission in UC.