Histological, But Neither Clinical Nor Endoscopic Activity Predicts the Risk of Colectomy in Patients With Ulcerative Colitis Treated With Biologics

Background: Biological treatment failure is common in patients with ulcerative colitis (UC), but the predictive value of baseline histological activity is unknown.

Aims: We aimed to investigate the associations between baseline histological activity and outcomes after biological treatment in patients with UC.

Methods: Adult biological-naïve patients with UC (n = 150) were followed prospectively during biological treatment. Histological activity was assessed using the Nancy Index and Geboes score. Endoscopic activity was assessed using the Mayo Endoscopic Subscore (MES). Associations with outcomes were assessed in multivariable models. Associations between histological, endoscopic, and biochemical activity were assessed using Spearman's correlation.

Results: In biological-treated patients with UC, severe histological activity at baseline was independently associated with colectomy risk during the induction period (Nancy 2 vs 4: odds ratio [OR] 0.18, 95% CI 0.01-0.61, P = 0.024; Nancy 3 vs 4: OR 0.12, 95% CI 0.02-0.63, P = .019; Geboes 3 vs 5: OR 0.06, 95% CI 0.00-0.57, P = .033; Geboes 4 vs 5: OR 0.13, 95% CI 0.01-0.69, P = 0.032) and total follow-up (Nancy 2 vs 4: HR 0.23, 95% CI 0.06-0.98, P = 0.046; Nancy 3 vs 4: HR 0.13, 95% CI 0.04-0.47, P = 0.002; Geboes 4 vs 5: HR 0.28, 95% CI 0.08-0.93, P = 0.038). Meanwhile, baseline MES was not independently associated with colectomy risk. Histological activity was correlated with MES and the levels of C-reactive protein, hemoglobin, and albumin, but not calprotectin.

Conclusions: Severe histological activity at baseline as characterized by a higher Nancy Index or Geboes score independently predicted colectomy risk in biological-treated UC patients, whereas MES did not. Thus, histological assessment should be encouraged before initiating biological treatment.