Use of confocal laser endomicroscopy to predict relapse of ulcerative colitis

Background: Assessment of inflammatory activity in patients with ulcerative colitis (UC) is crucial to the prediction of relapse. Confocal laser endomicroscopy (CLE) is an accurate tool for assessing inflammatory activity in UC patients. This study aimed to evaluate whether CLE could be used to predict UC relapse reliably. Methods: In total, forty-three patients with documented UC were analyzed in this study. Patients identified as having obvious active inflammation by conventional colonoscopy were excluded. The mucosa of each patient's sigmoid colon and rectum was assessed by CLE before targeted biopsies were taken. The patients were then followed up for at least 12 months to evaluate relapse according to the Simple Clinical Colitis Activity Index. The correlation between CLE classification and UC relapse was evaluated. Results: Seventeen of 20 patients with histologically confirmed normal or chronic inflammation were diagnosed as having non-active inflammation by real-time CLE and 22 of 23 patients with histologically confirmed acute inflammation were diagnosed as having active inflammation by CLE. The sensitivity, specificity, and accuracy of CLE in real-time diagnosis of active inflammation were 95.7%, 85%, and 90.7%, respectively. The agreement between CLE and conventional histology was excellent (kappa value = 0.812). Two of 18 (11.1%) patients who were classified as having non-active inflammation by CLE relapsed, while 16 of 25 (64%) patients classified as having as active inflammation relapsed. The relapse rate of patients with active inflammation was significantly higher than of those with non-active inflammation (P < 0.001). Conclusions: CLE is comparable to conventional histology in predicting relapse in patients with UC.