Early course of newly diagnosed moderate-to-severe ulcerative colitis in Korea: Results from a hospital-based inception cohort study (MOSAIK)

The Potential of Molecular Remission: Tissue Neutrophil Elastase Is Better Than Histological Activity for Predicting Long-Term Relapse in Patients With Ulcerative Colitis in Endoscopic Remission

BACKGROUND

Growing interest exists in deep remission, beyond clinical and endoscopic remission, to enhance long-term prognosis in patients with ulcerative colitis (UC). Our study aimed to evaluate the risk of relapse according to tissue expression levels of calprotectin and neutrophil elastase (NE) in patients with quiescent UC.

METHODS

Rectal biopsies were performed on 218 patients with UC in clinical and endoscopic remission. Histological activity was prospectively scored using the Robarts Histological Index. Tissue calprotectin and NE levels were evaluated using immunohistochemistry. Optimal tissue calprotectin and NE cutoffs for relapse were determined using log-rank analysis. Cox proportional hazard analyses evaluated relapse risk factors.

RESULTS

Tissue calprotectin and NE levels were significantly higher in patients with histological activity than in those in histological remission (P < .001). The optimal cutoffs of tissue calprotectin and NE for relapse were 10.61 and 22.08 per mm2, respectively. The 3-year clinical relapse risk was significantly lower in the low-tissue NE group than in the high-tissue NE group (P = .009); however, it did not differ between the low- and high-tissue calprotectin group (P = .094). In multivariate analyses, a low level of tissue NE expression was independently associated with a lower risk of 3-year clinical relapse (adjusted hazard ratio = 0.453, 95% confidence interval = 0.225-0.911, P = .026), unlike histological index and tissue calprotectin.

CONCLUSIONS

In patients with UC who have achieved clinical and endoscopic remission, tissue expression of NE is a better predictor of long-term relapse than histological activity.

Inflammatory bowel disease in Korea: epidemiology and pathophysiology

Inflammatory bowel disease (IBD) refers to a group of disorders, including Crohn's disease and ulcerative colitis, that exhibit similar but distinct manifestations. These diseases are characterized by refractory and chronic inflammation of the bowel. IBD is usually accompanied by severe symptoms. When a patient presents with suspected IBD, physicians encounter various challenges in terms of diagnosis and treatment. In addition, given such characteristics, the associated medical expenses gradually increase. Although IBD was formerly known as a disease of Western countries, the incidence and prevalence are increasing in Korea. Korean investigators have accumulated a great deal of knowledge about the regional characteristics and epidemiology of the disease, especially via well-organized, joint cohort studies. Against this background, this article describes the epidemiology of IBD in Korea compared to that in the West. In addition, an overview of the pathophysiology of the disease is provided, focusing on the latest results.