What is ulcerative colitis?
Ulcerative colitis is a life-long (chronic) inflammatory bowel disease that causes inflammation and ulceration (sores) in the large intestine (colon). Patients with ulcerative colitis often experience diarrhoea, bloody stools, weight loss and abdominal pain. When patients experience symptoms, the disease is considered "active", whereas when symptoms are not present the disease is considered to be "in remission".
What is a histologic scoring index?
A histologic tissue sample (biopsy) can be taken from a patient's colon during colonoscopy. A colonoscopy is a non-surgical procedure used to view the large intestine. Once the tissue sample is taken, it is placed (mounted) on a glass slide and looked at using a microscope. A histologic scoring index is a system used to assess the patient's disease severity using the tissue sample.
What did the researchers investigate?
It is important that histologic scoring indices are valid (i.e. they accurately measure what they are supposed to measure). The researchers identified histologic scoring indices that have been validated.
What did the researchers find?
The researchers found that 11 out of the 30 histologic scoring indices that exist have been partially validated. The Nancy Index and the Robarts Histopathology Index have undergone the most validation compared to the other nine indices. However, none of the currently available histologic scoring indices have been fully validated. In order to determine the ideal index to measure histologic healing in UC, more research is required. The ideal index would need to be fully validated.
The Nancy Index and the Robarts Histopathology Index have undergone the most validation in that four operating properties including reliability, content validity, construct validity (hypothesis testing) and criterion validity have been tested. However, none of the currently available histologic scoring indices have been fully validated. In order to determine the optimal endpoint for histologic healing in UC, more research is required. The optimal index would need to be fully validated.
Disease activity can be determined using clinical, endoscopic or histologic criteria in patients with ulcerative colitis (UC). Persistent disease activity is associated with poor outcomes. Histologic disease activity has been shown to be associated with relapse, colectomy and colorectal cancer. The ability to objectively evaluate microscopic disease activity using histology is important for both clinical practice and clinical trials. However, the operating properties of the currently available histologic indices remain unclear.
A systematic review was undertaken to identify and evaluate the development and operating characteristics of histologic disease activity indices used to assess disease activity in people with ulcerative colitis.
We searched MEDLINE, EMBASE, PubMed, CENTRAL and the Cochrane IBD Review Group Specialized Trials Register from inception to 2 December 2016 for applicable studies. There were no language or document type restrictions.
Any study design (e.g. randomized controlled trials, cohort studies, case series) that evaluated a histologic index in patients with UC were considered for inclusion. Eligible patients were adults (> 18 years), diagnosed with UC using conventional clinical, radiographic, endoscopic and histologic criteria.
Two authors (MHM and CEP) independently reviewed the titles and abstracts of the studies identified from the literature search. A standardized form was used to assess eligibility of trials for inclusion and for data extraction.
Two authors (MHM and CEP) independently extracted and recorded data, which included the number of patients enrolled, number of patients per treatment arm, patient characteristics including age and gender distribution, and the name of the histologic index. Outcomes (i.e. intra-rater reliability, inter-rater reliability, internal consistency, content validity, criterion validity, construct validity, responsiveness, and feasibility) were recorded for each trial.
In total, 126 reports describing 30 scoring indices were identified through the screening process. Eleven of the 30 scoring indices have undergone some form of index validation. Intra-rater reliability was assessed for eight scoring indices. Inter-rater reliability was evaluated for all 11 of the scoring indices. Three of the indices underwent content validation. Two of the included scoring indices assessed criterion validity. Six of the included scoring indices explored content validity. Two of the included scoring indices were tested for responsiveness.