Development of the Harvey-Bradshaw Index-pro (HBI-PRO) Score to Assess Endoscopic Disease Activity in Crohn's Disease

Background: There is a need for better, less-invasive disease activity indices that provide a representative assessment of endoscopic disease activity. We developed a new clinical score that incorporates the Harvey-Bradshaw index [HBI] with modified patient-reported outcomes [PROp] and physician [clinician]-reported outcomes [PROc] and assessed its ability to measure endosopic disease activity in ileocolonic Crohn's disease [CD].

Methods: A cohort of 88 CD patients undergoing colonoscopy was accrued in a prospective fashion. In total, 48 of the subjects were CD cases and 40 had already undergone a post-operative ileocolonic resection [post-op CD]. Each patient underwent multiple, endoscopist-blinded assessments including: HBI score, a PROp question asking for patient perception of disease activity status, a PROc question for clinician perception of disease activity status and C-reactive protein [CRP]. Active endoscopic disease was defined as Simple Endoscopic Score for CD [SES-CD] ≥ 3 for CD subjects and Rutgeerts score > i1 for post-op CD subjects.

Results: Clinical remission as defined by the HBI did not accurately reflect endoscopic remission as defined by the SES-CD (area under the curve [AUC] = 0.54). Combining the HBI with PROp and PROc scores and then further adding CRP significantly improved the correlation with SES-CD [AUC = 0.78 and AUC = 0.88, respectively, p < 0.00001]. In post-op CD, HBI-defined remission also performed poorly against endoscopic remission defined by the Rutgeerts score [AUC = 0.52]. Combining HBI with PROp and the PROc scores and then further adding CRP did not significantly improve the model [AUC = 0.65 and AUC = 0.61, respectively, p = NS].

Conclusion: In CD, the HBI correlates poorly with endoscopic disease activity. However, the HBI-PRO score, which incorporated PROp, PROc, CRP and HBI, significantly improved its ability to predict endoscopic activity in ileocolonic CD without prior surgery.