Search

Background Faecal calprotectin (FC) and faecal immunochemical tests (FIT) have the disadvantage of requiring faecal samples. It has been reported that prostaglandin E–major urinary metabolite (PGE-MUM) values correlate with Mayo endoscopic scores (MESs) for ulcerative colitis (UC). However, there has been no report that PGE-MUM can determine endoscopic remission under remission phase UC, nor comparative study of PGE-MUM with FC and FIT. Thus, we aimed to examine the association between PGE-MUM values and the colonoscopy (CS) results of patients in the remission phase of UC, and to compare the accuracy of using PGE-MUM vs. that of using FC or FIT values for determining endoscopic remission. Methods Patients diagnosed with UC who were under clinical remission and had planned to undergo CS from August 2017 to March 2019 were enrolled. FC levels were measured and FITs were performed on the day of CS; PGE-MUM was measured either the day before or after CS. Three physicians independently scored the CS findings (MES, Modified Mayo Endoscopic Score [MMES], and UC endoscopic index of severity [UCEIS]) while blinded from clinical information. We analysed the differences in PGE-MUM values between two groups, which were divided between those that did achieve and those that did not achieve the following scores: (1) MES 0 point, (2) MES 1 point, (3) modified MES 0 point, (4) modified MES ≤1 point, (5) UCEIS 0 point, (6) UCEIS ≤2 points. In addition, the accuracy of PGE-MUM, FC, and FIT with respect to determining the achievement of (1) through (6) were compared by using areas under the receiver operating characteristics curves. Patients with altered UC activity between the day of PGE-MUM measurement and CS, and those who received NSAIDs on the day of PGE-MUM measurement, were excluded from the analysis. Results Of the 125 enrolled subjects, 30 patients were excluded (urine specimens not submitted, 11; poor stool specimens, 6; NSAIDs users, 10; clearly altered UC activity, 3). The remaining 95 patients (average age 48.2 years, 57 males, and 54 patients with total colitis type), were eligible for analysis. The median PGE-MUM values (in µg/g·Cr) for groups that did or did not achieve (1) through (6) were as follows: (1) 14.6/17.2, p = 0.106; (2) 14.9/20.5, p = 0.039; (3) 14.5/17.4, p = 0.059; (4) 14.1/21.8, p < 0.001; 5) 14.5/17.4, p = 0.059; (6) 14.7/22.2, p = 0.003. The areas under the receiver operating characteristics curves for PGE-MUM/FC/FIT used for determining the achievement of 1) through 6) were as follows: (1) 0.597/0.664/0.682, (2) 0.692/0.74/0.825, (3) 0.613/0.686/0.692, (4) 0.794/0.82/0.786, (5) 0.613/0.686/0.692 and (6) 0.778/0.824/0.825. Conclusion PGE-MUM is equally as effective as FC and FIT for determining the achievement of endoscopic remission.