McDonald, John WD

Abstract Background Regulatory guidance for Crohn’s disease trials recommends coprimary efficacy end points that evaluate both symptoms and mucosal inflammation. We aimed to characterize the operating properties of commonly used disease activity assessments alone and in combination. Methods Endoscopic and clinical data were available for 129 participants from the Study of Biologic and Immunomodulator Naïve Patients in Crohn’s Disease trial. Readers scored the Simple Endoscopic Score for Crohn’s Disease and the Crohn’s Disease Endoscopic Index of Severity using standardized conventions. Index reliability was determined using intraclass correlation coefficients. Index responsiveness was assessed using standardized effect sizes based upon treatment assignment. Outcomes were evaluated for optimal sensitivity to treatment effect. Results Substantial inter-rater reliability was observed when the Simple Endoscopic Score for Crohn’s Disease and Crohn’s Disease Endoscopic Index of Severity were used as continuous measures (intraclass correlation coefficient, 0.64; 95% confidence interval [CI], 0.50-0.73; and 0.62 95% CI, 0.36-0.77) compared with moderate reliability when dichotomized (0.46; 95% CI, 0.26-0.65; and 0.51; 95% CI, 0.00-0.78). The Simple Endoscopic Score for Crohn’s Disease, Crohn’s Disease Endoscopic Index of Severity, patient-reported outcome-2, and Crohn’s Disease Activity Index were similarly responsive (standardized effect size, 0.43, 95% CI, 0.05-0.81; 0.38, 95% CI, 0.0-0.76; 0.53, 95% CI, 0.15-0.91). A composite outcome of Crohn’s Disease Activity Index score <150 and Crohn’s Disease Endoscopic Index of Severity score <6 was most sensitive to treatment effect (28.9%; 95% CI, 11.0%-46.8%; P = .003). Conclusion Endoscopic indices were more reliable as continuous measures. Composite outcomes including endoscopy improved sensitivity to treatment effect.

SummaryBackgroundThe optimal ulcerative colitis biopsy protocol is unclear.AimTo evaluate the number of biopsies required to accurately assess microscopic disease activity in ulcerative colitisMethodsBiopsies from patients with ≥4 rectosigmoid samples, and clinical and endoscopic data, were retrospectively obtained from a prospective biobank. Histology and endoscopic videos were read blindly. A 4‐biopsy Robarts Histopathology Index (RHI) reference score, consisting of the worst item‐level ratings from four biopsies, was compared to 1‐, 2‐ and 3‐biopsy estimates. Agreement was determined using bivariate errors‐in‐variable regression analysis (acceptance interval: ±8.25). Endoscopic activity and disease location subgroup analyses were also performed.ResultsForty‐six patients had ≥4 rectosigmoid biopsies available (N = 287). The 2‐biopsy (tolerance interval: −7.66, 4.79) and 3‐biopsy (tolerance interval: −4.86, 3.46) RHI scores demonstrated acceptable agreement with 4‐biopsy scores. One‐biopsy scores demonstrated unacceptable agreement (tolerance interval: −13.99, 7.78). Mean RHI scores using the 2‐, 3‐ and 4‐biopsy approaches were similar (6.1 ± 9.6 P = 0.36; 6.8 ± 10.5, P = 0.7; 7.5 ± 11.2), whereas the 1‐biopsy estimate was lower (4.4 ± 8.1, P = 0.06). Histological remission rates were identical for the 2‐, 3‐ and 4‐biopsy methods (65.2%, P = 1.0). Subgroup analysis demonstrated that three biopsies were required in patients with endoscopically active disease. Sampling additional colonic locations yielded lower histological remission rates compared to rectosigmoid sampling alone (33.3% vs 61.9%, P = 0.1).ConclusionsA minimum of two — conservatively, three — biopsies are required to reliably assess disease activity in a single colonic segment using the RHI. Further studies are needed of endoscopically active patients and sampling locations. These results have implications for biopsy strategies in clinical trials and practice.