Calabrese 2007.
| Methods | Randomized, unblinded, open‐label study | |
| Participants | Patients (n = 819) who presented to clinic, underwent a colonoscopy because of chronic watery diarrhoea and were diagnosed with microscopic colitis (aged 19–68 years; n = 64; 23 with collagenous colitis and 41 with lymphocytic colitis) Clinical components of diagnosis: Chronic or recurrent non‐bloody diarrhea Histological components of diagnosis: Increased chronic inflammatory infiltrate (plasma cells, lymphocytes, eosinophils) in the lamina propria; increased number of intraepithelial lymphocytes, damage to surface epithelium, with flattening of epithelial cells and/or epithelial loss and detachment and minimal crypt architecture distortion; specific to the diagnosis of collagenous colitis was a subepithelial collagen band >10 um thick, which entraps superficial capillaries, with an irregular lacy appearance at the lower edge of the basement membrane "Patients with a clear correlation between symptoms and [consumption] of drugs (e.g. NSAIDS, ticlopidine, PPI) were excluded" |
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| Interventions | Mesalazine 800 mg po tid (n = 20 with lymphocytic colitis and 11 with collagenous colitis) vs. mesalazine 800 mg po tid + cholestyramine 4 g po od (n = 21 with lymphocytic colitis and 12 with collagenous colitis) for 6 months A 24‐month treatment free follow was also performed A second round of 6 month‐therapy was offered if patients relapsed in follow‐up |
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| Outcomes | Primary outcomes: Clinical response: "Complete response was complete resolution of diarrhoea. Partial response was improvement but not resolution of diarrhoea Histological response: Normalization of histologic pattern at the end of 6 months Secondary outcomes: 24‐month follow‐up with coloscopies and biopsies, annually; adverse events; and days to remission or relapse, as well as various lab data (routine blood biochemistry and hematological counts, C‐reactive protein, antinuclear antibodies blood assay, serum T4 and thyroid stimulating hormone; IgA‐IgG antigliadin, antiendomysium, IgG anti tTG antibody blood assays; and parasitic‐bacterial, fecal‐stool, and hemo‐occult test |
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| Notes | "Relapse was defined as stool frequency greater than three soft or liquid stools per day" | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Randomization was performed with a computer generated list |
| Allocation concealment (selection bias) | Unclear risk | Not described in published study |
| Blinding (performance bias and detection bias) All outcomes | High risk | Quote: "open‐label" Quote: "All biopsies were analyzed by a single experienced pathologist in a blinded fashion" |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | 3 of 23 patients with collagenous colitis were lost to follow‐up over a 24 month period The treatment groups and reasons for the missing data were not reported |
| Selective reporting (reporting bias) | Unclear risk | Outcomes were not pre‐specified in the methods section of the manuscript |
| Other bias | Low risk | Study appeared to be free of other forms of bias |