Abstract
INTRODUCTION: Microscopic colitis (MC) is a common cause of chronic diarrhea with limited long-term data. MC consists of 2 distinct histopathological diagnoses; Lymphocytic colitis (LC) marked by >20 intraepithelial lymphocytes (IELs) per 100 epithelial cells (ECs) and collagenous colitis (CC) characterized by > or < 20 IELs/100 ECs and a thickened subepithelial collagen band (>10 microns). Recently, variant forms with fewer characteristic features have been reported under different names; “incomplete collagenous colitis (CCi)” and “incomplete lymphocytic colitis (LCi)” raising concern that CCi or LCi may represent different manifestations during the disease course or different stages of disease development. METHODS: We conducted a natural language search of the pathology records at our institution from 2008 to 2018 using the words “lymphocytic colitis” and “collagenous colitis.” The total sample included patients with either a diagnosis of MC or MCi (CCi/LCi). Chart review was performed to obtain data on demographics, comorbidities, medication, diagnosis, treatment and outcomes. Data were analyzed for descriptive statistics. Logistic regression was used to estimate the unadjusted effects of different variables on MC. RESULTS: A total of 216 patients (88.32% white, 80.56% females) with mean age 67 ± 16 were studied; 50% had CC, 40.3% had LC and 9.7% had MCi. The majority (52.3%) were smokers and 21.8% of females were using some form of hormonal therapy (Table 1). There was a statistically significant association between the use of tricyclic antidepressants (TCAs) and LC compared with CC (OR 3.23, 95% CI 1.18-8.80, P = 0.02; Table 2). Smoking, statins, aspirin and beta-blockers were significantly associated with CC compared with MCi (all P < 0.05; Table 3); 29 (13.4%) patients with unresolved symptoms underwent repeat colonoscopies with biopsies. One case of MCi resolved, 8 (72.7%) out of 11 cases of LC resolved, 2 (18.2%) continued to be LC and 1 (9.1%) transformed to CC, 8 (47.1%) out of 17 cases of CC resolved, 8 (47.1%) continued to be CC and 1 (5.9%) transformed to LC. CONCLUSION: The majority of patients had CC. TCA use was more likely to be associated with LC than CC. MCi was less likely to be associated with smoking and medications compared with CC. Biopsies from repeat colonoscopies in some patients revealed changes in the pathological diagnoses raising the question of interchangeability of MC (CC to LC and vice versa). However, our results need to be prospectively validated in a larger population.
Highlights
Microscopic colitis (MC) is a common cause of chronic, watery diarrhea with limited long-term data
Consistent with previous studies, this study shows that MC predominantly affects females, and the mean age at diagnosis is 67+/−16 years, suggesting that our study population is adequately representative of the population of MC patients
The odds of Lymphocytic colitis (LC) in reference to Collagenous colitis (CC) were significantly higher for those using tricyclic antidepressants (TCAs), a new finding that has not been previously reported
Summary
Microscopic colitis (MC) is a common cause of chronic, watery diarrhea with limited long-term data. The prevalence of MC exceeds 20 per 106 in many countries [1,2,3,4,5] and MC is found in approximately 10–15% of Microscopic Colitis: Epidemiology and Outcomes patients with chronic watery diarrhea undergoing colonoscopy with biopsy, with higher detection rates in the elderly and females [6]. CCi or LCi may represent different manifestations during the disease course or different stages of disease development [7]. Substantial clinical and histological overlap between LC and CC has been described, raising the suspicion that both conditions are two histological manifestations of the same entity, possibly representing different manifestations during the disease course or different stages of disease development [1]. We aim to describe the local epidemiology and risk factors for MC and describe histological changes in a sub-group of patients with MC who underwent follow up colonoscopy after treatment
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