Diagnosis Of Microscopic Colitis Research Articles

Psychiatric disorders among 5800 patients with microscopic colitis: A nationwide population-based matched cohort study.

Microscopic colitis (MC) is an inflammatory condition of the large intestine. Primarily diagnosed in middle-aged and older adults, the incidence of the disease has increased markedly during the past decades. While MC is associated with a reduced quality of life, large-scale studies on the association with future psychiatric disorders are lacking. We conducted a nationwide matched cohort study in Sweden from 2006 to 2021. Through a nationwide histopathology database (the ESPRESSO study), we identified 5,816 patients with a colorectal biopsy consistent with MC. These patients were matched with 21,509 reference individuals from the general population, all of whom with no previous record of psychiatric disorders. From 2006-2021, 519 patients with MC (median age 64.4 years (interquartile range = 49.5-73.3)) and 1,313 reference individuals were diagnosed with psychiatric disorders (9.9 vs. 6.5 events per 1,000 person-years), corresponding to one extra case of psychiatric disorder in 29 patients with MC over 10 years. After adjustments, the hazard ratio (HR) for psychiatric disorders was 1.57 (95% confidence interval [CI]=1.42-1.74). We found significantly elevated estimates up to 10 years after MC diagnosis and a trend towards higher risk with increasing age. Specifically, we observed increased risks for unipolar depression, anxiety disorders, stress-related disorders, substance abuse, and suicide attempts.In sibling-controlled analysis the aHR was 1.76 (95%CI=1.44-2.15). Patients with MC are at increased risk of incident psychiatric disorders compared to the general population.

Inflammatory eye disease is a risk factor for future microscopic colitis: A nationwide population-based matched case control study.

Microscopic colitis (MC) is an inflammatory disorder of the colon. To date, the relationship between inflammatory eye diseases and MC is unclear. To assess whether inflammatory eye disease (iridocyclitis and episcleritis) is a risk factor for MC. We conducted a nationwide matched case control study in Sweden leveraging the ESPRESSO-study (a Swedish database containing data on all biopsies from the gastrointestinal tract from 1965 to 2017). In total, we identified 14,338 patients with biopsy-verified MC (diagnosed from 1981 to 2017). Patients with MC were matched (by age, sex, county and year of birth) with 68,753 controls from the general population and the occurrence of preceding inflammatory eye diseases (defined as diagnosis of episcleritis or iridocyclitis) in the two groups was compared. Multivariable adjusted odds ratios (aORs) were calculated using conditional logistic regression conditioned on the matching variables. A majority of patients with MC were women (71.9%) and the median age at MC diagnosis was 63.3years (interquartile range (IQR)=50.7-72.6). Some 225 (1.6%) MC patients had an earlier record of inflammatory eye disease compared with 614 (0.9%) in controls. These figures corresponded to an aOR of 1.77 (95% CI=1.52-2.07) for inflammatory eye diseases in patients with MC. Compared to siblings, the aOR for previous inflammatory eye diseases in MC was 1.52 (95% CI=1.17-1.98) and patients treated with budesonide, as a proxy for clinically significant disease, had a somewhat higher aOR for previous inflammatory eye diseases. Inflammatory eye diseases are more common in patients subsequently being diagnosed with MC. Our findings highlight that these conditions may have shared causes and inflammatory pathways and are of clinical interest to gastroenterologists, ophthalmologists and general practitioners.

Number of intraepithelial lymphocytes and presence of a subepithelial band in normal colonic mucosa differs according to stainings and evaluation method

Chronic watery diarrhea is a frequent symptom. In approximately 10% of the patients, a diagnosis of microscopic colitis (MC) is established. The diagnosis relies on specific, but sometimes subtle, histopathological findings. As the histology of normal intestinal mucosa vary, discriminating subtle features of MC from normal tissue can be challenging and therefore auxiliary stainings are increasingly used. The aim of this study was to determine the variance in number of intraepithelial lymphocytes (IELs) and presence of a subepithelial band in normal ileum and colonic mucosa, according to different stains and digital assessment. Sixty-one patients without diarrhea referred to screening colonoscopy due to a positive feacal blood test and presenting with endoscopically normal mucosa were included. Basic histological features, number of IELs, and thickness of a subepithelial band was manually evaluated and a deep learning-based algorithm was developed to digitally determine the number of IELs in each of the two compartments; surface epithelium and cryptal epithelium, and the density of lymphocytes in the lamina propria compartment. The number of IELs was significantly higher on CD3-stained slides compared with slides stained with hematoxylin-and-eosin (HE) (p<0.001), and even higher numbers were reached using digital analysis. No significant difference between right and left colon in IELs or density of CD3-positive lymphocytes in lamina propria was found. No subepithelial band was present in HE-stained slides while a thin band was visualized on special stains. Conclusively, in this cohort of prospectively collected ileum and colonic biopsies from asymptomatic patients, the range of IELs and detection of a subepithelial collagenous band varied depending on the stain and method used for assessment. As assessment of biopsies from patients with diarrhea constitute a considerable workload in the pathology departments digital image analysis is highly desired. Knowledge provided by the present study highlight important differences that should be considered before introducing this method in the clinic.

Microscopic Colitis and Risk of Incident Psoriasis: A Nationwide Population-Based Matched Cohort Study.

Microscopic colitis (MC) has been associated with several immune-mediated diseases including psoriasis, but earlier research has been limited to psoriasis occurring before MC. Data from large-scale cohort studies investigating MC and risk of future psoriasis are lacking. To examine the association between MC and psoriasis. In a nationwide, population-based, matched cohort study in Sweden from 2007 to 2021, we identified 8404 patients with biopsy-verified MC (diagnosed in 2007-2017), 37,033 matched reference individuals, and 8381 siblings without MC. Information on MC was obtained through the ESPRESSO cohort (a Swedish histopathology database with nationwide coverage). Using Cox regression, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for psoriasis up until 2021. During a median follow-up of 9.2 years (interquartile range = 6.7-11.7), 179 MC patients and 440 reference individuals were diagnosed with psoriasis (241.1 vs 131.8 events per 100,000 person-years), corresponding to one extra case of psoriasis in 91 patients with MC over 10 years. After adjustment for the matching variables (birth year, sex, county of residence, and calendar period) and level of education, we computed an adjusted hazard ratio (aHR) of 1.82 (95% CI = 1.53-2.17). Stratified by sex, estimates were similar and when examining the aHR across different lengths of follow-up, we found significantly elevated estimates up to 10 years after MC diagnosis. Compared to MC-free siblings, the aHR was 1.85 (95% CI = 1.36-2.51). Patients with MC are at an almost doubled risk of psoriasis compared to the general population. Clinicians need to consider psoriasis in MC patients with skin lesions.

P1110 Collagenous colitis, clinical features, risk factors and treatment outcome: A large case series from the largest teaching Hospital in London, UK

Abstract Background Microscopic colitis is a cause of chronic watery, non-bloody diarrhoea diagnosed mainly on histology after taking biopsy from macroscopically normal colonoscopy. Thereby mainly two subtypes can be identified: Lymphocytic and collagenous colitis. So far, no biomarkers for the diagnosis of microscopic colitis have been identified. Here, we looked at, risk factors and treatment outcome of collagenous colitis in large series of cases. Methods In this study, we analysed all cases of collagenous colitis diagnosed from 2018-2022 in the Northeast London from 5 different teaching hospitals. 104 cases were identified and their electronic health record from hospital and from the primary care physicians (GP) were manually reviewed. Results In this cohort, 24% male, 76% female with ratio of (1:3), with mean age of 65 years. Forty percent were active or ex-smoker. PPI uses were associated with in 81% cases. While NSAIDS and statin were associated in 56% and 49% cases respectively. We also found that SSRI use were noted about 31% cases. Painless watery diarrhoea was the main cause for referral in 90% of cases, while complaint of abdominal pain noted in only 39% cases. Thirty-five (35%) cases noted to have history of weight loss. Forty-eight (48%) patients received treatment with Budesonide, 46% treated with loperamide, 5% with Immunomodulator or Biologics and 1% Bismuth Subsalicylates respectively. Other autoimmune disease were associated in 6% cases and 2% cases were associated with Coeliac disease. in Nineteen (19%) of cases symptoms improved immediately after stopping above associated drugs without any specific therapy. Twenty-five (25%) percent relapses 6 months after stopping of therapy. Patients present with abdominal pain, and arthralgia were significantly (p&amp;lt;0.001) higher risk of relapsing compared to patients with other symptoms. Conclusion In this large series of collagenous colitis, we found that in addition to associated drug use is not only risk, patient presents with abdominal pain and arthralgia have higher risk of relapse, after stopping of therapy of collagenous colitis . Further studies are needed to identify biomarker of this frustrating disease which has significant impact on patients of quality of life.

P1186 Unveiling the reality of Collagenous colitis: Beyond its Benign Façade

Abstract Background Microscopic colitis is a cause of chronic watery, non-bloody diarrhoea diagnosed mainly on histology after taking biopsy from essentially normal colonoscopy. Thereby mainly two subtypes can be identified: Lymphocytic and collagenous colitis. So far, no biomarkers for the diagnosis of microscopic colitis have been identified. Hower, despite being benign nature of this disease .it often trigger Two weeks wait (cancer path way) of the in the UK. Methods In this study, we analysed all cases of collagenous colitis diagnosed from 2018-2022 in the Northeast London from 5 different teaching hospitals. 104 cases were identified and their electronic health record from hospital and from the primary care physicians (GP) were manually reviewed. Results In this cohort, 24% male, 76% female with ratio of (1:3), with mean age of 65 years. Forty percent were active or ex-smoker. Painless watery diarrhoea was the main cause for referral in 90% of cases, 7% had painless bloody diarrhoea, whilst 3% complaint painful bloody diarrhoea. Abdominal pain noted in only 39% cases. Thirty-five (35%) cases noted to have history of weight loss. Among these patients, 27% had Haemoglobin &amp;lt; 130g/L, including 7% had &amp;lt;105g/L. Twenty nine percent had Faecal calprotectin (FCP) &amp;gt; 50 microgram/gm of stool and 14% had FCP &amp;gt;200. Seventeen percent had serum inflammatory marker raised CRP (normal 0-10). Thirteen percent (13%) of these patient trigger two weeks pathway referral as they had positive Faecal immunochemical test (FIT) which used for bowel cancer screening test, Twenty-seven (27%) presents did not require any treatment, got better after stopping suspected medication as a cause, while 73 % require treatment, of whom 5% require treatment with immunomodulator/ Biologics. Conclusion In this large series of collagenous colitis, we found that, despite being benign condition, it can present with alarming features which both health care provider and patient should be aware of, in order to avoid unnecessary anxiety. Further studies are needed to identify biomarker of this condition.

WARNING TO DELAY IN DIAGNOSING MICROSCOPIC COLITIS IN OLDER ADULTS. A SERIES OF CASES.

Microscopic colitis (MC) is a chronic inflammatory bowel disease causing non-bloody diarrhea, and several cases are undiagnosed as a hidden cause of chronic diarrhea. We aimed to report the symptoms, delay diagnosis and the treatment of MC in a case series. All patients were treated at a Gastroenterology reference office from May 2022 to June 2023. Personal history including preexisting disorders, use of medications and smoking habits were collected. The delay between the onset of symptoms and the correct diagnosis was informed. All patients consented to use budesonide MMX (Corament®) off label. During the study period, six Caucasoid patients were diagnosed with MC, five females and one male, between the ages of 65 and 74. All patients had comorbities and were taking multiple prescription drugs. Laboratory findings showed negative serology for celiac disease for all patients, normal levels of albumin and vitamin B12. The delay between the symptoms and the MC diagnosis varied from 2 months to 6 years. All patients had a previous diagnosis of irritable bowel syndrome. All patients were in complete clinical remission during the treatment and referred no side effects of the drug. Older females using high-risk medications are suggestive of MC. Preventing delay in the diagnosis of MC is crucial to improvement in patients´ quality of life. Budesonide MMX appears to be effective, safe and well-tolerated. • Microscopic Colitis is a chronic inflammatory bowel disease causing non-bloody diarrhea. • Several cases are undiagnosed and can be a hidden cause of chronic diarrhea. • Treatment with budesonide MMX (Corament®, off label) was effective and safe.

The association between drugs and repeated treatment with budesonide in patients with microscopic colitis: a retrospective observational study.

Smoking and the use of non-steroidal anti-inflammatory drugs (NSAIDs) acetylsalicylic acid (ASA), proton pump inhibitors (PPIs), serotonin reuptake inhibitors (SSRIs), and statins have been associated with microscopic colitis (MC). We investigated whether these factors were associated with repeated budesonide treatments in patients diagnosed with MC. Retrospective observational study. All patients with a histologically verified diagnosis of MC at our clinic between the years 2006 and 2022 were identified. Baseline factors and drugs prescribed before and after diagnosis were registered. The influence of risk factors on the odds of having a prescription of oral budesonide and the odds of having a second course of budesonide was studied. Patients with MC (n = 183) with a mean age of 62.3 years [standard deviation (SD): 13.3 years] were followed for a median of 5 years (25th-75th percentile 4-10 years) after diagnosis. In all, 138 patients (75%) had at least one prescription of budesonide after diagnosis, and 90 patients (49%) had at least one clinical relapse treated with budesonide. Patients who had been prescribed NSAIDs within 1 year before clinical relapse had higher odds for clinical relapse [odds ratio (OR): 3.70, 95% confidence interval (CI): 1.06-12.9] but there was no increased risk for clinical relapse for the use of ASA (OR: 0.99, 95% CI: 0.39-2.90), PPIs (OR: 1.09, 95% CI: 0.45-2.63), SSRI (OR: 1.41, 95% CI: 0.82-2.44), or statins (OR: 0.83, 95% CI: 0.35-1.99). No association was seen between being a smoker and/or being prescribed NSAID, ASA, PPI, SSRI, and statins at baseline and the odds of having a prescription of oral budesonide within 1 year after diagnosis. The risk of being prescribed a second course of budesonide is associated with receiving a prescription of NSAIDs but not with the use of ASA, PPIs, SSRIs, and statins.

Microscopic colitis and risk of incident rheumatoid arthritis: A nationwide population-based matched cohort study.

Microscopic colitis (MC) has been linked to several autoimmune conditions. Results from previous studies on the association with rheumatoid arthritis (RA) have been inconsistent. To assess the risk of future RA in MC. We conducted a nationwide matched cohort study in Sweden of 8179 patients with biopsy-verified MC (diagnosed in 2007-2017), 36,400 matched reference individuals and 8202 siblings without MC, with follow-up until 2021. Information on MC was obtained from all of Sweden's regional pathology registers (n = 28) through the ESPRESSO cohort. Data on incident RA were collected from the National Patient Register. Using Cox regression, we calculated adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). During a median follow-up of 9.1 years (interquartile range = 6.7-11.7), 73 MC patients and 183 reference individuals from the general population were diagnosed with RA (99 vs. 55 events per 100,000 person-years), equivalent to one extra case of RA in 226 patients with MC followed for 10 years. These rates corresponded to an aHR of 1.83 (95% CI = 1.39-2.41). The aHR was highest during the first year of follow-up (2.31 [95% CI = 1.08-4.97]) and remained significantly elevated up to 5 years after MC diagnosis (aHR 2.16; 95% CI = 1.42-3.30). Compared to siblings, without MC, the aHR was 2.04 (95% CI = 1.18-3.56). Patients with MC are at a nearly two-fold risk of developing RA compared to the general population. Knowledge of this increased risk may expedite evaluation for RA in patients with MC presenting with joint symptoms and/or arthralgia, thus preventing delay until RA diagnosis.

Regional differences in the incidence of lymphocytic and collagenous colitis over time

Background In microscopic colitis (MC), the incidence has increased over the last decades. The aim of the present study was to determine the incidence of lymphocytic (LC) and collagenous colitis (CC) in the county Skåne (Scania), southern Sweden, during the period 2010–20 with focus both on the temporal and spatial variations. Methods The MC diagnosis was retrieved from the biopsy registries at the Departments of Pathology. Established diagnostic criteria (increased lymphocyte count, inflammation in lamina propria and in CC a collagen band) were used for diagnosis. Age, gender, date for diagnosis and municipality of residence were retrieved for all patients. Results In total 1985 patients could be identified with a mean age of 62.9 years (SD 15.7) whereof 1415 were women. The incidence for CC was stable with a total age-standardized rate (ASR) per 100 000 person-years of 6.34, (range 4.6–8.1). In LC the ASR was 7.90 (range 1.7–15.2) but increased markedly 2015–20 reaching 15.2 in 2019. Also, the northwest part of the region showed significantly higher ASR:s of LC during the last part of the decade in comparation to the whole region. Conclusions The incidence of CC was stable during the period while LC differed substantially in a way that indicates that it most probably must be two different disease entities. In LC, in view of the marked and rapid increase, although no definitive explanation could be found, causative environmental factors could be contemplated, why further studies are indicated.

Microscopic Colitis: Pathogenesis and Diagnosis

Microscopic colitis is a type of inflammatory bowel disease and is classified as either collagenous colitis or lymphocytic colitis. The typical presentation is chronic watery diarrhea. The disease occurs more frequently in women aged 60–65 years and is increasing in incidence. The pathophysiology of microscopic colitis remains poorly understood and has not been well-described with possible several pathogeneses. To date, the diagnosis of microscopic colitis depends on histological tissue obtained during colonoscopy. Other non-invasive biomarkers, such as inflammatory markers and fecal biomarkers, have been studied in microscopic colitis, but the results remains inconclusive. The approach to chronic diarrhea is important and being able to differentiate chronic diarrhea in patients with microscopic colitis from other diseases, such as inflammatory bowel disease, functional diarrhea, and malignancy, by using non-invasive biomarkers would facilitate patient management. The management of microscopic colitis should be based on each individual’s underlying pathogenesis and involves budesonide, bile acid sequestrants, or immunosuppressive drugs in refractory cases. Cigarette smoking and certain medications, especially proton pump inhibitors, should be eliminated, when possible, after the diagnosis is made.

The Utility of Fecal Calprotectin in the Diagnosis and Management of Microscopic Colitis.

The incidence of microscopic colitis has increased over time. To date, there is no specific biomarker for microscopic colitis, and the diagnosis relies on histopathological tissue obtained during colonoscopy which is an invasive and costly procedure. Unlike Crohn's disease and ulcerative colitis, the utility of fecal calprotectin in diagnosing or monitoring microscopic colitis has not been established, and studies on the role of fecal calprotectin in microscopic colitis are limited. In this retrospective study, we analyzed the utility of this biomarker in the diagnosis of microscopic colitis. The medical records of patients who have been diagnosed with collagenous colitis and lymphocytic colitis aged 18-89 years old were retrospectively reviewed. Patient characteristics were recorded in those who had fecal calprotectin measured. There were 198 patients who were diagnosed with collagenous colitis and lymphocytic between October 1, 2015, and July 31, 2022. Twenty-three patients had fecal calprotectin levels measured and were included in this study. The mean age was 51.7 ± 7.8 years in all groups. Thirteen patients were female. Six patients (26.1%) were diagnosed with collagenous colitis, and 17 patients (73.9%) were diagnosed with lymphocytic colitis. The fecal calprotectin cut-off in this lab is 50 μg/g stool. Median fecal calprotectin levels were 30.1 μg/g (15.6, 122.5), 19.5 μg/g (16.5, 64.6), and 33.2 μg/g (15.6, 134.9) in all groups, collagenous colitis, and lymphocytic colitis, respectively. The utility of fecal calprotectin in diagnosing microscopic colitis is limited. Our study suggests the diagnosis should be based on histopathology tissue obtained during colonoscopy.

MICROSCOPIC COLITIS: CONSIDERATIONS FOR GASTROENTEROLOGISTS, ENDOSCOPISTS, AND PATHOLOGISTS.

•Diagnosis of microscopic colitis necessitates effective communication among gastroenterologists, endoscopists, and pathologists. •The gastroenterologist should refer every patient with chronic watery diarrhea to perform a colonoscopy in spite of the benign course of the disease and the absence of alarm symptoms. •The endoscopist should take 2 or 3 biopsy samples of the colonic mucosa from the right and left colon, put in separate recipients, despite that the mucosa looked macroscopically normal. •The pathologist should be encouraged to use objective histological criteria to make the diagnosis. Microscopic colitis is a chronic inflammatory bowel disease characterized by non-bloody diarrhea that can range from mild to severe. It is difficult to attribute up to 10-20% of chronic diarrhea to microscopic colitis. The three determinants factors of the diagnosis are characteristic clinical symptoms, normal endoscopic picture of the colon, and pathognomonic histological picture. This manuscript aimed to update considerations and recommendations for professionals involved (gastroenterologist, endoscopists and pathologist) in the diagnosis of MC. In addition, a short recommendation about treatment.

Microscopic colitis - state of current knowledge on pathogenesis, diagnostics and treatment

Introduction and purpose Microscopic colitis is multicausal inflammatory bowel disease, which affects mostly elderly, particularly women. It is a cause of chronic, watery diarrhea. MC usually presents macroscopically normal, thus diagnosis requires colonoscopy and histological examination of colonic biopsies. MC doesn’t increase risk of colon cancer. However, it leads to impaired patients’ quality of life and reduced living activity. This review aims to sum up the current state of knowledge about symptoms, diagnosis and treatment of microscopic colitis. Material and methods This review was based on available data collected in the PubMed database, using the following keywords: „microscopic colitis”, “microscopic colitis treatment”, „microscopic colitis pathogenesis”, and “ microscopic colitis diagnosis”. ConclusionsDiagnosis of MC is often delayed due to similarity of clinical manifestation with other inflammatory bowel diseases, like IBS or IBD. Raising awareness about MC as a potential cause of chronic diarrhea can lead to earlier diagnosis and increased patients’ quality of life.

Microscopic Colitis: A Clinical Case

Microscopic colitis is an inflammatory bowel disease of unknown etiology that presents as chronic watery diarrhea with no endoscopic evidence of the bowel involvement but with the microscopic changes. Diagnosis of microscopic colitis is based on the histological examination of the intestinal biopsy and requires a highly qualified gastroenterologist, endoscopist and histologist. The article presents a clinical case of microscopic colitis in a 42-year-old patient, reflects the main stages of diagnosis and treatment of the patient.

Celiac disease and risk of microscopic colitis: A nationwide population-based matched cohort study.

An association has been reported between celiac disease (CD) and microscopic colitis (MC). However, large, population-based cohort studies are rare. To systematically examine the association between CD and MC in a large, nationwide cohort. We conducted a nationwide population-based matched cohort study in Sweden of 45,138 patients with biopsy-verified CD (diagnosed in 1990-2016), 223,149 reference individuals, and 51,449 siblings of CD patients. Data on CD and MC were obtained from all (n=28) pathology departments in Sweden. Adjusted hazard ratios (aHRs) were calculated using Cox regression. During follow-up, 452 CD patients and 197 reference individuals received an MC diagnosis (86.1 vs. 7.5 per 100,000person-years). This difference corresponded to an aHR of 11.6 (95% confidence interval [CI]=9.8-13.8) or eight extra MC cases in 1000 CD patients followed up for 10years. Although the risk of MC was highest during the first year of follow-up (aHR 35.2; 95% CI=20.1-61.6), it remained elevated even after 10years (aHR 8.1; 95% CI=6.0-10.9). Examining MC subtypes lymphocytic colitis (LC) and collagenous colitis (CC) separately, the aHR was 12.4 (95% CI=10.0-15.3) for LC and 10.2 (95% CI=7.7-13.6) for CC. MC was also more common before CD (adjusted odds ratio [aOR]=52.7; 95% CI=31.4-88.4). Compared to siblings, risk estimates decreased but remained elevated (CD and later MC: HR=6.2; CD and earlier MC: aOR=7.9). Our study demonstrated a very strong association of MC with CD with an increased risk of future and previous MC in CD patients. The magnitude of the associations underscores the need to consider the concomitance of these diagnoses in cases in which gastrointestinal symptoms persist or recur despite a gluten-free diet or conventional MC treatment. The comparatively lower risk estimates in sibling comparisons suggest that shared genetic and early environmental factors may contribute to the association between CD and MC.

Microscopic colitis is a risk factor for low bone density: a systematic review and meta-analysis.

Microscopic colitis (MC) is a chronic inflammatory disease of the large bowel characterized by watery diarrhea, substantially decreasing the patient's quality of life. Scarce data suggest that MC is associated with low bone density (LBD). We aimed to assess whether MC is a risk factor for LBD and the proportion of patients with MC having LBD. A systematic review and meta-analysis of studies reporting bone density measurements in MC patients. We systematically searched five databases from inception to October 16, 2021 (Pubmed, Embase, Cochrane, Scopus, and Web of Science). We used the random-effect model to calculate pooled odds ratios (ORs) and pooled event rates with 95% confidence intervals (CIs). To ascertain the quality of evidence of our outcomes, we followed the recommendations of the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Working Group. The systematic search yielded a total of 3046 articles. Four articles were eligible for quantitative synthesis. All of them used age- and sex-matched controls to evaluate LBD occurrence among patients with MC. The odds of having LBD were twofold increased (OR = 2.13, CI: 1.42-3.20) in the presence of MC, the odds of osteopenia occurrence were 2.4 (OR = 2.45, CI: 1.11-5.41), and of osteoporosis 1.4 (OR = 1.42, CI: 0.65-3.12). The proportion of LBD was 0.68 (CI: 0.56-0.78), osteopenia was 0.51 (CI: 0.43-0.58), and osteoporosis was 0.11 (CI: 0.07-0.16) among the MC population. Our findings' certainty of the evidence was very low following the GRADEPro guideline. Our data demonstrate that MC is associated with a twofold risk for LBD. Based on our findings, we suggest screening patients for bone mineral density upon diagnosis of MC. Further prospective studies with higher patient numbers and longer follow-up periods on this topic are needed. Our protocol was prospectively registered with PROSPERO (CRD42021283392).

Characteristics and outcomes of cancer patients with pre-existing microscopic colitis after exposure to PD-1 and PD-L1 inhibitors.

Immune checkpoint inhibitors (ICIs) are frequently associated with adverse events, often affecting the gastrointestinal tract. We conducted this study to determine the characteristics and outcomes of cancer patients with pre-existing microscopic colitis (MC) who underwent ICI treatment. In this retrospective study, we identified 10 patients with pre-existing MC who received ICIs at our center 01/2010-06/2020. Clinical characteristics and disease outcomes were recorded. Of 124 screened patients with MC before ICI exposure, 10 had sufficient data to be included in the study. Melanoma (40%) and lung cancer (30%) were the most prevalent cancer types, with 70% of stage IV cancer. Patients received either anti-programmed death 1 regimen (8, 80%) or anti-programmed death ligand 1 agent (2, 20%). Six patients (60%) had collagenous colitis, and 4 (40%) had lymphocytic colitis. The median time from MC diagnosis to ICI initiation was 4years, with 1 patient on budesonide within 2months of ICI initiation. Eight patients (80%) developed colitis exacerbations after ICI and required selective immunosuppression. One patient received a compassionate-use fecal transplantation. The median time from ICI to colitis exacerbation was 14days, with 40% and 50% of patients experiencing grade 3 diarrhea and grade 2 colitis, respectively, leading to hospitalization in 3 patients. Six patients received steroids and vedolizumab with no colitis recurrence. Of 8 patients who had colitis exacerbation, 6 resumed ICI therapy afterward; with 5 receiving concomitant vedolizumab for secondary prophylaxis. Our findings suggest that ICI exposure increases the risk of exacerbation of underlying colitis necessitating and responding to potent immunosuppression therapy.

Letter to the editor: response to 'Epidemiology and seasonal pattern in hospitalizations for microscopic colitis'.

We read with great interest the letter to the editor by Al-Taee et al. [1] on the seasonal pattern and epidemiology of hospitalizations for microscopic colitis (MC). Their study reviewed the 2016 National Inpatient Sample (NIS) and discussed all admissions for MC occurred between August and December, suggesting a seasonal pattern of MC. To further study this phenomenon, we analyzed NIS data from 2016 to 2019. Using ICD-10 codes, we identified all hospitalizations with a primary diagnosis code of MC (K52.83). We stratified hospitalizations into months and analyzed seasonal trends. We identified 5190 hospitalizations with a primary diagnosis of MC between January 2016 to December 2019. As described by Al-Taee et al. [1], MC was more commonly seen in southern (31.21%) and midwestern regions (30.25%). Females accounted for more than 80% of hospitalizations. Most patients admitted with a primary diagnosis of MC were White (88.34%) and elderly (70.81%). The prevalence of MC with regard to sex and race was comparable to that of 2016. The mean length of stay in these patients was 4.87 (+/-1.2 days), whereas total hospitalization charges were $37 247 (±1065.61). In 2016, admissions for MC were noted only between August and December, as discussed by Al-Taee et al. [1] However, starting in 2017, we noted admissions every month from January to December. The results are provided in Fig. 1. We excluded patients in 2016 and evaluated the consecutive years for a seasonal effect. We noticed that most admissions occurred in July (n = 500; 9.6%), followed by October (n = 460; 8.86%) and April (n = 450; 8.6%). The lowest number of admissions occurred in November (n = 310; 5.97%). Admissions for MC each month are presented in Fig. 1. There were 1195 admissions (24.81%) in the spring, 1315 in the summer (27.33%), 1195 in the fall (24.81%), and 1110 (23.05%) in the winter. Although Al-Taee et al. [1] reported that most admissions occur from August to December, our study revealed a slight predominance in the summer. Another study by LaSala et al. [2] reported a seasonal pattern of lymphocytic colitis, with higher cases in summer and fall, compared with winter months.Fig. 1.: Monthly admissions for microscopic colitis between 2016 to 2019.The limitations of this study were the same as that of the retrospective cross-sectional study by Al-Taee et al. [1] as the data source is the same for these two studies. Given the variable results in the two studies, it is too early to conclude that there is a definite seasonal pattern for MC. However, larger epidemiological studies may provide further information. Acknowledgements None. Conflicts of interest There are no conflicts of interest.

S190 Complete Colonoscopy vs Flexible Sigmoidoscopy to Diagnose Microscopic Colitis

Introduction: Microscopic colitis (MC) is a diagnosis made via biopsy, typically requiring a colonoscopy. Current European guidelines recommend performing a colonoscopy as rectal biopsies alone could miss the diagnosis. The purpose of the study is to retrospectively analyze the data on patients diagnosed with MC and determine if complete colonoscopy with right and transverse colon biopsies is needed to make a diagnosis or if flexible sigmoidoscopy with rectal and left sided biopsies would suffice Methods: We performed a retrospective review of data from 1/1/1999 to 1/12/2019 on patients with a pathologic diagnosis of MC at Gundersen Health System. This study was conducted after the approval by the Gundersen Health System institutional review board. We included 342 patients with a histological diagnosis of either collagenous, lymphocytic, or MC. No patients were excluded. We compared the frequencies of left sided versus random colonoscopy biopsy diagnosis of microscopic colitis using Kappa coefficient as a measure of interrater reliability for agreement. A p-value was calculated to evaluate for significant difference. (Table) Results: Out of 342 patients, 129 patients had positive pathologic diagnosis from left sided biopsy sites alone while 184 patients had positive biopsy results from random biopsy sites. This frequency indicates 53.8% of the diagnoses for MC could be missed by performing left sided biopsies alone. The Kappa coefficient of -0.7896 indicates no agreement between obtaining a pathologic diagnosis from left sided biopsy compared to random with a (p < .0001). None of these patients were using budesonide at the time of biopsy. Conclusion: This study highlights agreement with current European guidelines for the recommendation of doing a complete colonoscopy for the diagnosis of MC. Prior studies including Tanaka M, et al. and Offner FA, et al. have shown consistent results with 30 patients but our study included a larger patient population. Having a Kappa coefficient of -0.7896 indicates moderate disagreement between positive biopsy diagnosis from left and random biopsy sites. While this study may not change current guidelines, it adds validity to them and highlights the importance of performing a colonoscopy and not just flexible sigmoidoscopy to diagnose microscopic colitis. Table 1. - Patient Characteristics Patient Characteristics Frequency Collagenous Colitis 113 Lymphocytic Colitis 218 Microscopic Colitis 11 Tubular Adenomas 7