TABLE 1.
Summary of UEG/EMCG statements and recommendations for MC
| Section and number | Statement/recommendation | Level of evidence | Grade of recommendation | Voting |
|---|---|---|---|---|
| Section 1 | Epidemiology and risk factors | |||
| Section 1.1 | The pooled overall incidence rate of MC is estimated to be 11.4 (95% CI: 9.2–13.6) cases per 100,000 person‐years. The incidence of CC and LC ranges from 0.6 to 16.4 cases per 100,000 person‐years and from 0.6 to 16.0 cases per 100,000 person‐years, respectively. | High | NA | 100% |
| Section 1.2 | The pooled overall prevalence of MC is estimated to be 119 (95% CI: 73–66) per 100,000 persons, with an overall prevalence of 50.1 per 100,000 person‐year for CC and 61.7 per 100,000 persons for LC. | High | NA | 94% |
| Section 1.3 | The pooled frequency of MC in patients with chronic watery diarrhoea is 12.8% (95% CI: 10–16), with significant heterogeneity (I 2 = 93.6%). | Moderate | NA | 100% |
| Section 1.4 | Former, but especially current smoking is associated with an increased risk of both CC and LC. | Moderate | NA | 100% |
| Section 1.5 | The risk of developing CC or LC is higher in women than in men. | High | NA | 100% |
| Section 1.6 | There is insufficient evidence to evaluate the influence of smoking cessation on the disease course. | Low | NA | 78% |
| Section 1.7 | Chronic or frequent use of PPI, NSAID or SSRI is associated with an increased risk of MC. However, this does not imply a causal relationship. | Low | NA | 94% |
| Section 1.8 | We suggest to consider withdrawal of any drugs with a suspected chronological relationship between drug introduction and onset of diarrhoea. | Very low | Weak in favour | 97% |
| Section 1.9 | MC does not increase the risk of colorectal cancer or adenoma. A special surveillance colonoscopy program is not recommended. | Low | Strong in favour | 100% |
| Section 2 | Pathogenesis | |||
| Section 2.1 | Pathogenesis of MC is complex and multifactorial. It may include luminal factors, immune dysregulation and genetic predisposition. | Low | NA | 100% |
| Section 3 | Clinical manifestation | |||
| Section 3.1 | The most common symptom of MC is chronic watery, nonbloody diarrhoea, which is frequently associated with concomitant symptoms including faecal urgency, nocturnal stools and faecal incontinence. nocturnal stools and faecal incontinence. | Moderate | NA | 97% |
| Section 3.2 | MC diagnosis should be ruled out in patients fulfilling the criteria for functional bowel disease, especially in presence of MC risk factors and/or in absence of IBS‐therapy response. | Moderate | NA | 93% |
| Section 3.3 | Health‐related quality of life is impaired in patients with MC, depending on the activity and severity of the disease and concomitant comorbidities. | Moderate | NA | 100% |
| Section and number | Statement/recommendation | Level of evidence | Grade of recommendation | Voting |
|---|---|---|---|---|
| Section 3.4 | In the absence of a formally validated metric of disease activity, disease activity and clinical remission in MC should be assessed by the Hjortswang criteria (clinical remission: mean of <3 stools/day and a mean <1 water stool/day during a 1‐week registration). | Moderate | NA | 100% |
| Section 4 | Diagnosis | |||
| Section 4.1 | Endoscopic findings are recognised with increased frequency in patients with MC, however they are nonspecific. | Low | NA | 95% |
| Section 4.2 | The histopathologic criteria of CC are a thickened subepithelial collagenous band ≥10 μm combined with an increased inflammatory infiltrate in lamina propria. The criteria apply to haematoxylin and eosin‐stained slides. | Moderate | NA | 89% |
| Section 4.3 | The histopathologic criteria of LC are an increased number of intraepithelial lymphocytes ≥20 per 100 surface epithelial cells combined with an increased inflammatory infiltrate in lamina propria and a not significantly thickened collagenous band (<10 μm). The criteria apply to haematoxylin and eosin‐stained slides. | Moderate | NA | 100% |
| Section 4.4 | Incomplete MC comprises incomplete CC (defined by a thickened subepithelial collagenous band >5 μm but <10 μm) and incomplete LC (defined by >10 IELs but <20 IELs and a normal collagenous band). Both types show a mild inflammatory infiltrate in the lamina propria. The criteria apply to haematoxylin and eosin‐stained slides. | Low | NA | 95% |
| Section 4.5 | We recommend ileocolonoscopy with biopsies from at least the right and left colon. | High | Strong in favour | 100% |
| Section 4.6 | We recommend against histological monitoring in patients with MC. | Very low | Strong in favour | 100% |
| Section 4.7 | Faecal calprotectin is not useful to exclude or monitor MC. | Moderate | NA | 100% |
| Section 4.8 | We recommend screening for coeliac disease in patients with MC. | High | Strong in favour | 100% |
| Section 4.9 | Testing for bile acid diarrhoea is not part of routine diagnostic workup in MC. | Low | NA | 83% |
| Section 4.10 | Testing for bile acid diarrhoea can be considered in patients who experience nonresponse to budesonide treatment. | Low | Strong in favour | 82% |
| Section 5 | Treatment | |||
| Section 5.1.1 | We recommend using oral budesonide to induce remission in patients with CC. | Moderate | Strong in favour | 100% |
| Section 5.1.2 | We recommend using oral budesonide to induce remission in patients with LC. | Low | Strong in favour | 100% |
| Section 5.2.1 | Oral budesonide is effective to maintain remission in patients with CC. | Moderate | Strong in favour | 94% |
| Section 5.2.2 | We suggest using oral budesonide to maintain remission in patients with LC. | Very low | Weak in favour | 84% |
| Section 5.3.1 | There is no increased risk of serious adverse events with budesonide in MC. | Low | NA | 100% |
| Section 5.3.2 | The risk of osteoporotic bone fractures seems not be increased in budesonide treated MC patients, although prolonged use might be associated with a decrease of bone mineral density. | Low | NA | 97% |
| Section 5.4 | We recommend against treatment with mesalazine in patients with MC for induction of remission. There are no studies for maintenance. | Low | Strong against | 94% |
| Section 5.5 | There is not enough evidence to recommend bismuth subsalicylate in patients with MC. | Very low | Strong against | 92% |
| Section 5.6 | There is not enough evidence to recommend the use of loperamide in MC. Given the documented effect in patients with chronic diarrhoea, the expert's opinion favours the use of this drug in mild disease. | Very low | Strong in favour | 100% |
| Section 5.7 | In patients with MC and bile acid diarrhoea we suggest treatment with bile acid binders. | Very low | Weak in favour | 100% |
| Section 5.8 | There is not enough evidence to recommend antibiotics for treatment of MC. | Very low | Strong against | 100% |
| Section 5.9 | We recommend against use of probiotics for treatment of MC. | Low | Strong against | 100% |
| Section 5.10 | We recommend against the use of prednisolone or other corticoste roids than budesonide for the treatment of MC. | Low | Strong against | 100% |
| Section 5.11 | We recommend treatment with thiopurines, anti‐TNF drugs or vedolizumab in selected patients with MC who fail to respond to budesonide to induce and maintain clinical remission. We recommend against the use of methotrexate in patients with MC. | Low | Strong in favour | 97% |
| Section 5.12 | Surgery can be considered in selected MC patients as last option if all medical therapy fails. | Very low | Weak in favour | 100% |
Abbreviations: CC, collagenous colitis; CI, confidence interval; EMCG, European Microscopic Colitis Group; LC, lymphocytic colitis; IELs, intraepithelial lymphocytes; IBS, irritable bowel syndrome; MC, microscopic colitis; PPI, proton pump inhibitor; TNF, tumour necrosis factor; NSAID, nonsteroidal anti‐inflammatory drugs; SSRI, selective serotonin reuptake inhibitor; NA, not applicable; UEG, United European Gastroenterology.