Defining clinical criteria for clinical remission and disease activity in collagenous colitis

Collagenous colitis is a chronic inflammatory bowel disease accompanied mainly by nonbloody diarrhea. The objectives of treatment are to alleviate the symptoms and minimize the deleterious effects on health-related quality of life (HRQOL). There is still no generally accepted clinical definition of remission or relapse. The purpose of this study was to analyze the impact of bowel symptoms on HRQOL and accordingly suggest criteria for remission and disease activity based on impact of patient symptoms on HRQOL.

The design was a cross-sectional postal survey of 116 patients with collagenous colitis. The main outcome measures were 4 HRQOL questionnaires: the Short Health Scale, the Inflammatory Bowel Disease Questionnaire, the Rating Form of IBD Patient Concerns, and the Psychological General Well-Being Index, and a 1-week symptom diary recording number of stools/day and number of watery stools/day.

Severity of bowel symptoms had a deleterious impact on patients' HRQOL. Patients with a mean of ≥3 stools/day or a mean of ≥1 watery stool/day had a significantly impaired HRQOL compared to those with <3 stools/day and <1 watery stool/day.

We propose that clinical remission in collagenous colitis is defined as a mean of <3 stools/day and a mean of <1 watery stool per day and disease activity to be a daily mean of ≥3 stools or a mean of ≥1 watery stool.