Introduction

Endoscopic confirmation of treatment response is recommended in ulcerative colitis (UC). However, colonoscopy (CS) is not well accepted by patients and approximately 50% of patients starting treatment do not undergo CS in the following 2 years. Fecal calprotectin (FC), a non-invasive biomarker of mucosal inflammation, is widely available, but a universal cut-off value applicable to all patients is not yet known. Intestinal ultrasound (IUS) is emerging as an accurate tool for monitoring treatment response. In particular, the Milan ultrasound criteria (MUC) is a validated score to assess endoscopic activity in UC. MUC < 6.2 accurately detects Mayo endoscopic score (MES) < 1 (REF 1 e 2).

Aims & Methods

The aim of this study was to evaluate the performance of non-invasive approaches in detecting treatment response in UC in an outpatient setting, using CS as reference standard.
All consecutive patients with UC seen in the outpatient clinic in one week and scheduled for a colonoscopy the following week were eligible. Treatment response was graded according to: a) symptoms (partial Mayo score, PMS < 2), b) biomarkers (FC < 250 mcg/g and C-reactive protein, CRP < 5 mg/L), c) Milan Ultrasound Criteria (MUC < 6.2) and d) combined approach with MUC and FC (MUC < 6.2 + FC < 50 mcg/g or MUC < 6.2 + FC > 50 < 250 mcg/g). Receiver Operating Characteristic (ROC) curve analysis was used to compare the non-invasive approaches, using Mayo endoscopic score as reference standard (response defined by MES < 1).

Results

97 patients with UC were enrolled (60 males, median age 39 years). 77 patients were in biologics or small molecules, 29 in steroids and 5 in immunosuppressants. Response to treatment (defined by MES < 1) was correctly identified in 64% of cases based on symptoms, 68% using biomarkers, 80% using MUC, and 83% with a combined approach. Biomarkers-based detection was not superior to symptoms (0.695 vs. 0.671; p= 0.74). Ultrasound-based detection was superior to both symptoms (0.822 vs 0.671; p= 0.015) and biomarkers (0.822 vs 0.695; p= 0.046). Combined approach was superior to symptoms (0.825 vs 0.671; p= 0.016) and biomarkers (0.825 vs 0.695; p=0.004), but not to IUS (0.825 vs 0.822; p= 0.943).

Conclusion

The use of an ultrasound-based approach in combination with FC increases our ability to assess treatment response in UC patients in real time, possibly avoiding CS.

References

1) Allocca M, Fiorino G, Bonovas S, et al. Accuracy of humanitas ultrasound criteria in assessing disease activity and severity in ulcerative colitis: A prospective study. J Crohns Colitis 2018;12:1385–91. doi:10.1093/ecco-jcc/jjy107.
2) Allocca M, Filippi E, Costantino A, et al. Milan ultrasound criteria are accurate in assessing disease activity in ulcerative colitis: external validation. United Eur Gastroenterol J 2021;9:438–42. doi:10.1177/2050640620980203.