Faculty Bibliography

The inflammatory bowel diseases (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), are chronic, progressive, inflammatory conditions of the gastrointestinal tract. Imbalance in the gut microbial community, or dysbiosis, and the subsequent immune response, represent the critical relationship between genetic susceptibility, microbes, and environment factors, that result in IBD. Gastrointestinal pathogens - a common cause of dysbiosis - have been implicated as an environmental trigger in new onset IBD, as well as flare of existing IBD. In this article, we systematically review clinical data regarding the association between specific gastrointestinal pathogens and IBD. Numerous bacteria, viruses, fungi, and parasites have been implicated in the pathogenesis of IBD, and exacerbations of existing disease. In this article, we will also specifically discuss the less recognized microbes that have an inverse association with IBD, including certain bacterial pathogens, such as Helicobacter pylori, and parasites, such as Trichuris species. Future prospective and experimental studies are required to establish causality and clarify potential mechanisms of enteric pathogens in modifying the risk and course of IBD.

BACKGROUND:There are concerns that individuals with chronic immune-mediated diseases are at increased risk of COVID-19 and related severe adverse outcome, including intensive care admission or death. We aimed to explore the absolute and relative risk of severe COVID-19 in inflammatory bowel disease (IBD). METHODS:This population-based cohort study used nationwide registers in Sweden, with 67,292 individuals with a diagnosis of IBD 1969-2017 (Crohn's disease, n = 21,599; ulcerative colitis: n = 43,622; IBD-unclassified: n = 2071) and alive on 1 February 2020. Patients with IBD were matched to up to five controls from the general population (n = 297,910). Cox regression estimated hazard ratios (HRs) for (i) hospital admission with laboratory-confirmed COVID-19 as the primary diagnosis, and (ii) severe COVID-19 (composite outcome consisting of (a) COVID-19 intensive care admission, or (b) death from COVID-19 or (c) death within 30 days of COVID-19 hospital admission), were calculated. Analyses were conditioned on age, sex, calendar period, and county and adjusted for other comorbidities. RESULTS:Between 1 February and 31 July 2020, 179 (0.27%) IBD patients and 500 (0.17%) general population controls were admitted to hospital with COVID-19 (adjusted HR [aHR] = 1.43; 95% CI = 1.19-1.72). The corresponding numbers for severe COVID-19 was 65 (0.10%) and 183 (0.06%; aHR = 1.11; 95% CI = 0.81-1.52). Adjusted HRs were similar in Crohn's disease and ulcerative colitis. In a propensity score-matched model taking comorbidity into account until 2016, the increased risk for COVID-19 hospital admission remained (aHR = 1.32; 1.12-1.56), but there was no increased risk of severe COVID-19 (aHR = 1.12; 0.85-1.47). CONCLUSIONS:While individuals with IBD were more likely to be admitted to hospital for COVID-19 than the general population, the risk of severe COVID-19 was not higher.

BACKGROUND:There is wide variation in the quality of care of hospitalized patients with inflammatory bowel disease (IBD). Prior studies have demonstrated that a specialized inpatient IBD service improves short-term outcomes. In this study, we assessed the impact of a dedicated IBD service on the quality of care and long-term outcomes. METHODS:This retrospective cohort study included adult patients admitted for a complication of IBD between March 2017 and February 2019 to a tertiary referral center. In March 2018, a dedicated inpatient IBD service co-managed by IBD gastroenterologists and colorectal surgeons was implemented. Quality of care outcomes included C. difficile stool testing, confirmed VTE prophylaxis administration and opiate avoidance. Long-term outcomes were clinical remission, IBD-related surgery, ED visits, and hospital readmissions at 90 days and 12 months. RESULTS:In total, 143 patients were included; 66 pre- and 77 post-implementation of the IBD service. Fifty-two percent had ulcerative colitis and 48% had Crohn's disease. After implementation, there was improvement in C.difficile testing (90% vs. 76%, P = 0.04), early VTE prophylaxis (92% vs. 77%, P = 0.01) and decreases in narcotic use (14% vs. 30%, P = 0.02), IBD-related ED visits at 90 days (7% vs 18%, P = 0.03) and 12 months (16% vs 30%, P = 0.04), and IBD readmissions at 90 days (16% vs. 30%, P = 0.04). There were no differences in rates of clinical remission or surgery. CONCLUSIONS:The creation of a dedicated inpatient IBD service improved quality of IBD care and reduced post-discharge ED visits and readmissions and broader implementation of this strategy may help optimize care of hospitalized IBD patients.

BACKGROUND AND AIMS/OBJECTIVE:Gastrointestinal infections have been linked to changes in the composition and function of gut microbiome and development of inflammatory bowel diseases. We therefore sought to examine the relationship between gastroenteritis and risk of microscopic colitis (MC). METHODS:We conducted a case-control study of all adult MC patients diagnosed between 1990-2016 in Sweden matched to up to 5 general population controls according to age, sex, calendar year, and county. Cases of MC were identified using SNOMED codes from the ESPRESSO study, a cohort of gastrointestinal pathology reports from all 28 pathology centers in Sweden. We used logistic regression modeling to estimate adjusted odds ratios (aORs) and 95% CIs. RESULTS:Through December of 2016, we matched 13,468 MC cases to 64,479 controls. The prevalence of previous diagnosed gastrointestinal infection was 7.5% among MC patients which was significantly higher than in controls (3.0%, Pcomparison <0.001). After adjustment, gastroenteritis was associated with an increased risk of MC (aOR 2.63; 95%CI=2.42-2.85). Among specific pathogens, Clostridioides difficile (aOR 4.39, 95%CI=3.42-5.63), Norovirus (aOR 2.87, 95%CI=1.66-4.87) and Escherichia species (aOR 3.82, 95%CI=1.22-11.58) but not Salmonella species were associated with an increased risk of MC. The association between gastrointestinal infections and risk of MC was stronger for collagenous subtype (aOR 3.23, 95% CI 2.81-3.70) as compared to lymphocytic colitis (aOR = 2.51, 95% CI 2.28-2.76, Pheterogeneity = 0.005). The associations remained significant after adjustment for immune-mediated conditions and polypharmacy and when compared to unaffected siblings. CONCLUSION/CONCLUSIONS:In a nationwide study, we found that gastrointestinal infection, particularly Clostridioides difficile is associated with an increased risk of subsequent MC.

BACKGROUND:Differentiating between enteric infection and relapse of inflammatory bowel disease (IBD) is a common clinical challenge. Few studies have evaluated the impact of multiplex gastrointestinal polymerase chain reaction (GI PCR) pathogen panels on clinical practice compared to stool culture. Our aim was to compare the impact of PCR stool testing to conventional stool testing in outpatients presenting with relapse of IBD. METHODS:In a retrospective cohort study of outpatients with IBD presenting to NYU Langone Health with flare from September 2015 to April 2019, we compared patients who underwent stool testing with GI PCR to age-, sex-, and IBD-subtype-matched patients who underwent culture and ova and parasite exam (conventional testing). The primary outcome was IBD therapy escalation after testing. Secondary outcomes included rates of posttesting endoscopy, abdominal radiography, antibiotics, and IBD-related emergency department visits, hospitalizations, and abdominal surgeries. RESULTS:We identified 134 patients who underwent GI PCR matched to 134 patients who underwent conventional testing. Pathogens were more frequently identified on GI PCR (26 vs 5%; P < 0.01). We found that GI PCR was associated with less escalation in IBD therapy (16 vs 29%; P < 0.01) and fewer posttest endoscopies (10% vs 18%; P = 0.04), with no differences in IBD outcomes. On multivariate analysis, testing with GI PCR was associated with an odds ratio of 0.26 (95% confidence interval, 0.08-0.84; P = 0.02) for escalation of IBD therapies. CONCLUSIONS:Testing with GI PCR was associated with higher rates of pathogen detection and lower rates of IBD therapy escalation and endoscopy in the outpatient setting. These changes in management were not associated with a difference in IBD outcomes.

BACKGROUND & AIMS/OBJECTIVE:Restorative proctocolectomy with ileal pouch-anal anastomosis is a surgical procedure in patients with ulcerative colitis refractory to medical therapies. Pouchitis, the most common complication, is inflammation of the pouch of unknown etiology. To define how the intestinal immune system is distinctly organized during pouchitis, we analyzed tissues from patients with and without pouchitis and from patients with ulcerative colitis using single-cell RNA sequencing (scRNA-seq). METHODS:We examined pouch lamina propria CD45+ hematopoietic cells from intestinal tissues of ulcerative colitis patients with (n=15) and without an ileal pouch-anal anastomosis (n=11). Further in silico meta-analysis was performed to generate transcriptional interaction networks and identify biomarkers for patients with inflamed pouches. RESULTS:In addition to tissue-specific signatures, we identified a population of IL1B/LYZ+ myeloid cells and FOXP3/BATF+ T cells that distinguish inflamed tissues which we further validated in other single cell RNA-seq datasets from IBD patients. Cell type specific transcriptional markers obtained from single-cell RNA-sequencing was used to infer representation from bulk RNA sequencing datasets, which further implicated myeloid cells expressing IL1B and S100A8/A9 calprotectin as interacting with stromal cells, and Bacteroidiales and Clostridiales bacterial taxa. We found that non-responsiveness to anti-integrin biologic therapies in ulcerative colitis patients was associated with the signature of IL1B+/LYZ+ myeloid cells in a subset of patients. CONCLUSIONS:Features of intestinal inflammation during pouchitis and ulcerative colitis are similar, which may have clinical implications for the management of pouchitis. scRNA-seq enables meta-analysis of multiple studies, which may facilitate the identification of biomarkers to personalize therapy for IBD patients.

BACKGROUND:Inflammatory bowel disease (IBD) patients who have Clostridioides difficile infection (CDI) have worse outcomes. AIMS/OBJECTIVE:We aimed to determine whether such outcomes are the result of CDI or whether CDI occurs in patients who have more severe IBD. METHODS:This was a retrospective study of patients hospitalized for ≥ 2 IBD flares from 2010 to 2019. The primary outcome was time to IBD flare between hospitalizations. First, time to flare was compared between patients who were hospitalized for a flare complicated by CDI and subsequently for a CDI-negative flare (cohort A, denoted +/-) versus patients who were hospitalized for two CDI-negative flares (cohort B, -/-). Second, time between flares was compared within the subset of cohort A patients who had three flares (cohort C, -/+/-) before and after CDI. RESULTS:Time between flares was a median of 4 months (IQR 1-9) among 51 cohort A patients versus 12 months (IQR 6-38) among 51 cohort B patients (log-rank P < 0.01). In contrast, the median time between flares was similar within cohort C before and after CDI (log-rank P = 0.54). At time of the second IBD flare, patients in cohort A (+/-) were more likely to have moderate or severe disease compared to patients in cohort B (-/-). CONCLUSIONS:Patients with prior CDI had shorter time to subsequent IBD flare relative to their CDI-negative counterparts. This is not likely due to CDI itself because there was no difference in time between flares before versus after acquiring CDI. Rather, patients who acquire CDI may have more severe IBD.

BACKGROUND:Sacroiliitis is an inflammatory arthritis of the sacroiliac joints and is associated with inflammatory bowel disease (IBD). Yet, sacroiliitis often goes undiagnosed in IBD, and the clinical association between IBD disease activity and sacroiliitis is not well established. Patients with Crohn's disease (CD) often receive magnetic resonance enterography (MRE) to assess disease activity, affording clinicians the opportunity to evaluate for the presence of sacroiliitis. We aimed to identify the prevalence and disease characteristics associated with sacroiliitis in CD patients undergoing MRE. METHODS:All CD patients undergoing MRE for any indication between 2014 and 2018 at an IBD referral center were identified. The MREs were reviewed for the presence of sacroiliitis based on bone marrow edema (BME) and structural lesions. We analyzed demographics, IBD characteristics, clinical and endoscopic disease activity, and management between CD patients with and without sacroiliitis. RESULTS:Two hundred fifty-eight patients with CD underwent MRE during the study period. Overall, 17% of patients had MR evidence of sacroiliitis, of whom 73% demonstrated bone marrow edema. Female gender, back pain, and later age of CD diagnosis were associated with sacroiliitis (P = 0.05, P < 0.001, P = 0.04, respectively). Disease location and CD therapy were not associated with sacroiliitis on MRE. Clinical, endoscopic, and radiographic disease activity were not associated with sacroiliitis on MRE. CONCLUSION/CONCLUSIONS:Sacroiliitis is a common comorbid condition in CD. With limited clinical clues and disease characteristics to suggest sacroiliitis, physicians may utilize MRE to identify sacroiliitis, especially in CD patients with back pain.