Background and aims

Despite increasing interest in histologic remission as a treatment target in ulcerative colitis (UC), the accuracy of histologic findings in left colon in detecting pancolonic histologic remission is unknown.

Methods

In a retrospective cohort study of patients with endoscopically active pancolitis undergoing treat-to-target interventions, we evaluated the diagnostic accuracy of left-sided (distal to splenic flexure) histologic and endoscopic findings on colonoscopy for detecting histologic and endoscopic healing elsewhere in the colon.

Results

Of 86 patients with moderate to severely active pancolitis who underwent 2 consecutive colonoscopies during treat-to-target interventions, 38% and 51% achieved histologic and endoscopic remission, respectively. Substantial agreement (kappa, 0.67; 95% confidence interval (CI), 0.51-0.83) was observed in histologic findings between left and right colon on follow-up colonoscopy. Histologic, and endoscopic, findings in left colon showed excellent accuracy in detecting pancolonic histologic remission (area under the curve (AUC), 0.96 [95% CI, 0.93-1.0]; misclassification rate, 5.9%), histologic normalization (AUC, 1.0, 0%), endoscopic improvement (AUC, 0.95 [0.96-1.0], 3.5%) and endoscopic remission (AUC, 0.98 [0.96-1.00], 5.8%), respectively.

Conclusions

In patients with active pancolitis undergoing treat-to-target interventions, histologic and endoscopic findings in the left colon on colonoscopy have excellent accuracy for detecting pancolonic histologic remission, histologic normalization, endoscopic improvement, and endoscopic remission. Flexible sigmoidoscopy may suffice for monitoring histologic and endoscopic activity in patients with pancolitis.

Background & aims

Hospitalized patients with acute severe ulcerative colitis (ASUC) often require surgery. Although the tumor necrosis factor antagonist infliximab is an effective salvage therapy to prevent colectomy in patients with ASUC, optimal dosing is unclear. Calculated infliximab clearance has been associated with important outcomes in patients with ulcerative colitis, but its utility in patients with ASUC has not been established. We assessed the relationship between calculated the baseline infliximab clearance before infliximab salvage therapy and the requirement for colectomy in patients hospitalized for ASUC.

Methods

We obtained data from hospitalized patients with ASUC who initiated infliximab therapy. We then calculated the baseline infliximab drug clearance in these patients based on an existing formula. The primary aim was to compare clearance between patients who required colectomy 6 months later and patients who did not require colectomy. Receiver operating characteristic curve analyses evaluated clearance thresholds for colectomy. Multivariable logistic regression analysis evaluated factors associated with colectomy.

Results

In 39 patients with ASUC, the median baseline calculated clearance was higher in patients requiring colectomy at 6 months than in patients without colectomy (0.733 vs 0.569 L/d; P = .005). An infliximab clearance threshold of 0.627 L/d identified patients who required colectomy with 80.0% sensitivity and 82.8% specificity (area under the curve, 0.80). A higher proportion of patients with infliximab clearance of 0.627 L/d or more underwent colectomy within 6 months (61.5%) than patients with lower infliximab clearance values (7.7%) (P = .001). Multivariable analysis identified baseline infliximab clearance as the only factor associated with colectomy. The infliximab dose in the hospital was higher in patients who required colectomy. Results were similar at 30 days and 1 year.

Conclusions

In patients hospitalized with ASUC, higher values of calculated infliximab clearance before infliximab administration is associated with higher rates of colectomy. Although patients who required colectomies received higher doses, data on infliximab concentrations are lacking. Infliximab pharmacokinetic models are needed for patients with ASUC to allow comparative trials on clearance-based vs standard dosing.