Histologic remission predicts relapse-free survival in ulcerative colitis

Histologic remission using the validated Nancy histologic index (NHI) score is independently associated with a significantly longer relapse-free survival and appears to be a better therapeutic target than endoscopic remission in patients with ulcerative colitis (UC), reports a study.

“Histologic activity is recognized as an important predictor of relapse in UC patients,” the researchers said. “Current treatment targets aim at mucosal healing; however, many patients continue to have histologic activity.”

This retrospective cohort study examined histologic activity using the NHI score as a predictor of future relapse among UC patients in endoscopic and clinical remission who underwent a surveillance colonoscopy at a single tertiary centre between 2015 and 2018.

Clinical remission was characterized by partial Mayo score <2 and endoscopic remission by Mayo endoscopic subscore (MES) ≤1, while histologic remission was defined by NHI <2. The research team analysed the predictive factors associated with clinical relapse, the primary endpoint.

Overall, 184 UC patients were identified, with 74 satisfying the eligibility criteria. Of these, 33 (45 percent) showed histologic activity (NHI >1) upon enrollment. The median follow-up time was 42 months, with a median relapse-free period of 30 months.

In Kaplan-Meier analysis, patients with MES 0 (p=0.02) and histologic remission (p<0.0001) experienced significantly longer relapse-free survival. Multivariate analysis revealed that only histologic activity remained as an independent predictor of future clinical relapse (hazard ratio, 4.36, 95 percent confidence interval, 1.68‒11.27; p=0.002).