Pharmacist-Driven Therapeutic Infliximab Monitoring at the Point of Care Using Rapidly Assessed Drug Levels in Patients with Inflammatory Bowel Disease.

BACKGROUND: Therapeutic monitoring of infliximab is limited by the time lag between drug-level measurement and dose adjustment, along with the cost of dose escalation. Strategies for dose reduction in stable patients on maintenance infliximab at supratherapeutic levels are uncertain. This study determined the feasibility of a pharmacist-driven strategy for immediate dose adjustment using a sliding scale at the point of care in stable patients with inflammatory bowel disease on maintenance therapy. METHODS: Adult patients with stable disease undergoing maintenance therapy with infliximab infusions, 5 mg/kg every 8 weeks, were prospectively studied. Trough drug levels were assessed by a rapid assay (and later by ELISA) at all infusions for up to 12 months with immediate but quantitatively small dose adjustment according to a sliding scale targeting a therapeutic range of 3-7 mcg/mL. Disease activity was assessed both clinically and biochemically. RESULTS: The rapid assay and ELISA detected similar infliximab levels, and the strategy added approximately 30 minutes to the duration of infusion events. Only 20% of 48 patients (77% with Crohn disease) had baseline trough infliximab concentrations within the therapeutic range. This value increased 3-fold after 24 and 48 weeks of interventions. One in 2 patients had baseline supratherapeutic levels, and most were brought into the therapeutic range without a discernible impact on disease activity by 1 dose adjustment, but 2 or 3 adjustments were generally needed for 29% of patients with subtherapeutic levels. Overall, drug costs were reduced by 4%. CONCLUSIONS: Immediate dose adjustment after infliximab rapid assay performed by a pharmacist using a sliding scale is a feasible strategy. Supratherapeutic infliximab levels can be safely and quickly brought into the therapeutic range using small dose adjustments without affecting disease activity, offsetting (at least partly) costs associated with dose escalation.

Thiopurines and their optimization during infliximab induction and maintenance: A retrospective study in Crohn's disease.

BACKGROUND AND AIM: Combining therapy with a thiopurine is favored when commencing infliximab in Crohn's disease; however, the optimal 6-thioguanine nucleotide (TGN) level and how long to continue thiopurines after induction are uncertain. We aimed to compare outcomes after induction and during maintenance in combination therapy versus infliximab monotherapy in Crohn's and to examine whether TGN levels were associated with outcomes. METHODS: Crohn's patients induced with infliximab with or without concomitant thiopurines were retrospectively identified. Response to induction and clinical outcomes in subsequent 6-month maintenance semesters were analyzed. A TGN level ≥235 pmol/8 × 108 red blood cells was considered therapeutic. RESULTS: In 89 patients, response to induction was higher in combination therapy than monotherapy (74 vs 47%, P = 0.04). This benefit was only seen in patients with a therapeutic TGN (odds ratio 3.72, confidence interval 1.07-13.0, P = 0.04). Combination therapy during induction yielded a three times longer time to subsequent need for treatment escalation or treatment failure compared with monotherapy (29 vs 9 months, P = 0.01), with both therapeutic and subtherapeutic TGNs independent predictors on multivariate analysis. Among 370 semesters, there was no difference in outcomes between combination therapy and monotherapy (P = 0.42), nor when combination semesters were stratified by therapeutic versus subtherapeutic TGN (P = 0.56). In semester 1 only, a significantly higher remission rate was observed with therapeutic compared with subtherapeutic TGN (76% vs 33%, P = 0.02). CONCLUSIONS: Combination therapy dosed with an optimized thiopurine was superior to infliximab monotherapy for induction of response, durability of response, and clinical outcomes in the first 6 months following induction. Thereafter, combination therapy yielded no clinical advantage, supporting consideration of thiopurine withdrawal on a case-by-case basis.

Complementary and Alternative Medicines Used by Patients With Inflammatory Bowel Diseases.

Patients and physicians often have many questions regarding the role of complementary and alternative medicines (CAMs), or nonallopathic therapies, for inflammatory bowel diseases (IBDs). CAMs of various forms are used by more than half of patients with IBD during some point in their disease course. We summarize the available evidence for the most commonly used and discussed CAMs. We discuss evidence for the effects of herbs (such as cannabis and curcumin), probiotics, acupuncture, exercise, and mind-body therapy. There have been few controlled studies of these therapies, which have been limited by their small sample sizes; most studies have been uncontrolled. In addition, there has been a lack of quality control for herbal preparations. It has been a challenge to design rigorous, randomized, placebo-controlled trials, in part owing to problems of adequate blinding for psychological interventions, acupuncture, and exercise. These barriers have limited the acceptance of CAMs by physicians. However, such therapies might be used to supplement conventional therapies and help ease patient symptoms. We conclude that physicians should understand the nature of and evidence for CAMs for IBD so that rational advice can be offered to patients who inquire about their use. CAMs have the potential to aid in the treatment of IBD, but further research is needed to validate these approaches.

Low Mass Blood Peptides Discriminative of Inflammatory Bowel Disease (IBD) Severity: A Quantitative Proteomic Perspective.

Breakdown of the protective gut barrier releases effector molecules and degradation products into the blood stream making serum and plasma ideal as a diagnostic medium. The enriched low mass proteome is unexplored as a source of differentiators for diagnosing and monitoring inflammatory bowel disease (IBD) activity, that is less invasive than colonoscopy. Differences in the enriched low mass plasma proteome (<25 kDa) were assessed by label-free quantitative mass-spectrometry. A panel of marker candidates were progressed to validation phase and "Tier-2" FDA-level validated quantitative assay. Proteins important in maintaining gut barrier function and homeostasis at the epithelial interface have been quantitated by multiple reaction monitoring in plasma and serum including both inflammatory; rheumatoid arthritis controls, and non-inflammatory healthy controls; ulcerative colitis (UC), and Crohn's disease (CD) patients. Detection by immunoblot confirmed presence at the protein level in plasma. Correlation analysis and receiver operator characteristics were used to report the sensitivity and specificity. Peptides differentiating controls from IBD originate from secreted phosphoprotein 24 (SPP24, p = 0.000086, 0.009); whereas those in remission and healthy can be differentiated in UC by SPP24 (p = 0.00023, 0.001), α-1-microglobulin (AMBP, p = 0.006) and CD by SPP24 (p = 0.019, 0.05). UC and CD can be differentiated by Guanylin (GUC2A, p = 0.001), and Secretogranin-1 (CHGB p = 0.035). Active and quiescent disease can also be differentiated in UC and CD by CHGB (p ≤ 0.023) SPP24 (p ≤ 0.023) and AMBP (UC p = 0.046). Five peptides discriminating IBD activity and severity had very little-to-no correlation to erythrocyte sedimentation rate, C-reactive protein, white cell or platelet counts. Three of these peptides were found to be binding partners to SPP24 protein alongside other known matrix proteins. These proteins have the potential to improve diagnosis and evaluate IBD activity, reducing the need for more invasive techniques. Data are available via ProteomeXchange with identifier PXD002821.

Positioning intestinal ultrasound in a UK tertiary centre: significant estimated clinical role and cost savings.

Objective: Intestinal ultrasound (IUS) is an inexpensive, non-invasive method of diagnosing and monitoring inflammatory bowel disease (IBD). We aimed to establish the proportion of lower gastrointestinal endoscopies (LGIEs) and magnetic resonance enterographies (MREs) that could have been performed as IUS, the potential pathology miss-rates if IUS was used and the associated cost savings. Methods: All MREs and LGIEs performed for either assessment of IBD activity or investigation of possible IBD, performed at a single UK tertiary centre in January 2018, were retrospectively reviewed against predetermined criteria for IUS suitability. Case outcomes were recorded and cost of investigation if IUS was performed instead was calculated. Results: 73 of 260 LGIEs (28.1%) and 58 of 105 MREs (55.2%) met the criteria for IUS suitability. Among potential IUS-suitable endoscopy patients, one case each of a <5 mm adenoma and sessile serrated lesion were found; no other significant pathology that would be expected to be missed with IUS was encountered. Among IUS-suitable MRE patients, no cases of isolated upper gastrointestinal inflammation likely to be missed by IUS were found, and extraintestinal findings not expected to be seen on IUS were of limited clinical significance. The predicted cost saving over 1 month if IUS was used instead was £8642, £25 866 and £5437 for MRE, colonoscopy and flexible sigmoidoscopy patients, respectively. Conclusion: There is a significant role for IUS, with annual projected cost savings of up to almost £500 000 at our centre. Non-inflammatory or non-gastrointestinal pathology predicted to be missed in this cohort was of limited clinical significance.

Recurrent Campylobacter jejuni Infection in an Immunodeficient Patient Treated with Repeated Faecal Microbiota Transplant (FMT)-A Case Report.

There is limited evidence to guide successful treatment of recurrent Campylobacter infection in patients with common variable immunodeficiency (CVID) already managed on regular immunoglobulin therapy. The role of faecal microbiota transplant (FMT) is uncertain. We report a case of recurrent Campylobacter jejuni infection in a patient with CVID treated with repeated FMT with 18 months of symptom resolution prior to relapse.

Anogenital Crohn's Disease and Granulomatosis: A Systematic Review of Epidemiology, Clinical Manifestations, and Treatment.

BACKGROUND AND AIMS: Metastatic Crohn's disease is an extraintestinal cutaneous manifestation characterised by non-specific inflammatory lesions anatomically separate from the gut; genital involvement is rare. We conducted a systematic review of anogenital Crohn's disease and granulomatosis, to provide a synthesis of epidemiology, clinical features, and treatment outcomes. METHODS: A systematic search of the literature was conducted via MEDLINE, EMBASE, and the Cochrane database from inception to December 1, 2020. Two investigators extracted and analysed study data. Response and remission were defined as partial improvement or complete resolution of symptoms and examination findings, respectively. RESULTS: Of 9381 screened studies, 185 articles, [410 cases: 273 female, 137 male] were included. The predominant clinical features were oedema, ulcers, fissures, and hypertrophic lesions. Adults and children present similarly. Luminal Crohn's disease was diagnosed in nearly 80% of cases including 45-80% patients without gastrointestinal symptoms (time to inflammatory bowel disease [IBD] from anogenital Crohn's disease diagnosis [range] -43 to 11 years). Antibiotics, corticosteroids, thiopurines, and anti-tumour necrosis factor [TNF] therapy were the most frequently prescribed agents. At final follow-up, non-response, response, and remission rates were 37/304 [12%], 267/304 [88%], and 114/304 [38%], respectively. Oedema was associated with a poor response to topical therapy. Greater response rates to anti-TNF therapy were seen in patients prescribed concomitant immunomodulation [24/25, 96% vs 67/90, 74%, p = 0.02]. CONCLUSIONS: We provide an illustrative summary of the clinical presentation and treatment effectiveness of this rare, under-recognised condition, and a proposed algorithm for approach and management. Prospective studies with longer follow-up are required to define optimal treatment strategies.

Depression, anxiety, and stress among inflammatory bowel disease patients during COVID-19: A UK cohort study.

BACKGROUND AND AIM: Patients with chronic diseases are believed to be at increased risk of mental health conditions during the COVID-19 pandemic. We aimed to assess the incidence of psychological morbidity in inflammatory bowel disease (IBD) patients during the COVID-19 pandemic, explore for association with risk of severe COVID-19 and other factors, and establish patients' interest in psychological support. METHODS: A survey including the Patient Health Questionnaire-9, General Anxiety Disorder-7, and Perceived Stress Scale tools for depression, anxiety, and stress was administered to IBD patients from a tertiary center in London, United Kingdom, in June 2020. RESULTS: Two hundred seventy-four patients responded to the survey (57% response rate), with 271 (99%) completing it. Moderate-severe depression was observed in 61 (22.5%), while 49 (18%) had moderate-severe anxiety; 39 (14%) had both diagnoses. Mean (SD) stress score was 16.2 (7.4). There was no association between degree of severe COVID-19 risk and psychological morbidity. Flare symptoms and fatigue were associated with worse psychological morbidity, while accessibility of information regarding COVID-19 risk and reducing that risk was protective for depression (odds ratio [OR] 0.56 [0.33-0.94], P = 0.03), anxiety (OR 0.62 [0.4-0.96], P = 0.03), and stress (standardized ß-coefficient -0.15 [-0.28 to -0.03], P = 0.02). Seventy-nine (30%) respondents were interested in receiving psychological support during the pandemic, while 200 (76%) expressed interest beyond the pandemic. CONCLUSIONS: Although depression, anxiety, and stress among IBD patients during the pandemic were common, their frequency was similar to pre-pandemic rates and recent general population levels. Ensuring easy access to personalized risk information with targeted psychological support may mitigate psychological burden as patients reintegrate into society and deal with future COVID-19 waves.

A retrospective cohort study: pre-operative oral enteral nutritional optimisation for Crohn's disease in a UK tertiary IBD centre.

BACKGROUND: Low-quality evidence suggests that pre-operative exclusive enteral nutrition (E/EN) can improve postoperative outcomes in patients with Crohn's disease (CD). It is not standard practice in most centres. AIMS: To test the hypothesis that pre-operative EN in patients undergoing ileal/ileocolonic surgery for CD is associated with improved postoperative outcome. METHODS: We performed a single centre retrospective observational study comparing surgical outcomes in patients receiving pre-operative EN (≥600 kcal/day for ≥2 weeks) with those who received no nutritional optimisation. Consecutive adult patients undergoing ileal/ileocolonic resection from 2008 to 2020 were included. The primary outcome was postoperative complications <30 days. Secondary outcomes included EN tolerance, specific surgical complications, unplanned stoma formation, length of stay, length of bowel resected, readmission and biochemical/anthropometric changes. RESULTS: 300 surgeries were included comprising 96 without nutritional optimisation and 204 optimised cases: oral EN n = 173, additional PN n = 31 (4 of whom had received nasogastric/nasojejunal EN). 142/204 (69.6%) tolerated EN. 125/204 (61.3%) initiated EN in clinic. Patients in the optimised cohort were younger at operation and diagnosis, with an increased frequency of penetrating disease and exposure to antibiotics or biologics, and were more likely to undergo laparoscopic surgery. The optimised cohort had favourable outcomes on multivariate analysis: all complications [OR 0.29; 0.15-0.57, p < 0.001], surgical complications [OR 0.41; 95% CI 0.20-0.87, p = 0.02], non-surgical complications [OR 0.24 95% CI 0.11-0.52, p < 0.001], infective complications [OR 0.32; 95% CI 0.16-0.66, p = 0.001]. CONCLUSIONS: Oral EN was reasonably well tolerated and associated with a reduction in 30-day postoperative complications. Randomised controlled trials are required to confirm these findings.

An observational study of switching infliximab biosimilar: no adverse impact on inflammatory bowel disease control or drug levels with first or second switch.

BACKGROUND: Biologics account for a significant cost in inflammatory bowel disease (IBD) management; however, switching from infliximab originator to its biosimilars has enabled cost saving without compromising disease control. The effects on IBD activity and infliximab trough levels of a second switch to another biosimilar are, however, uncertain. AIMS: To assess the effects on disease activity and infliximab trough levels associated with switching from infliximab biosimilar CT-P13 to another biosimilar SB2 and compare outcomes in those switching for the first and second time. METHODS: IBD patients on CT-P13, including some previously switched from originator, were prospectively followed during a switch to SB2. C-reactive protein (CRP), trough infliximab level and clinical disease activity indices were collected at baseline, Infusion 3 or 4 ('early' after switch), and 1 year. RESULTS: One hundred eighty-six patients (n = 99 second switch) on stable infliximab dosing underwent switching. Compared with baseline, there was no significant change in CRP, clinical disease activity scores or median trough infliximab level at the early time point among first-switch (baseline vs early: 5.7 vs 6.6 µg/mL, P = 0.05) and second-switch (4.3 vs 4.9 µg/mL, P = 0.07) patients nor at 1 year (median infliximab trough levels, baseline vs 1 year, in first-switch [5.7 vs 5.7 µg/mL, P = 0.37] and second-switch [4.3 vs 4.7 µg/mL, P = 0.06] patients). The proportion of patients in clinical remission did not significantly change at the early (92% vs 91% at baseline, P = 0.75) or 1 year (95% vs 91% at baseline, P = 0.16) time points. There was no significant difference in time to loss of response between patients switching for the first or second time (P = 0.69). CONCLUSIONS: Switching from one infliximab biosimilar to another had no adverse impact on infliximab trough levels, and clinical and biochemical disease activity, regardless of whether switching for the first or second time.

Development of a Simple, Serum Biomarker-based Model Predictive of the Need for Early Biologic Therapy in Crohn's Disease.

BACKGROUND: Early or first-line treatment with biologics, as opposed to conventional immunomodulators, is not always necessary to achieve remission in Crohn's disease [CD] and may not be cost-effective. This study aimed to develop a simple model to predict the need for early biologic therapy, in order to risk-stratify CD patients and guide initial treatment selection. METHODS: A model-building study using supervised statistical learning methods was conducted using a retrospective cohort across two tertiary centres. All biologic-naïve CD patients who commenced an immunomodulator between January 1, 2004 and December 31, 2016, were included. A predictive score was derived using Cox regression modelling of immunomodulator failure, and was internally validated using bootstrap resampling. RESULTS: Of 410 patients [median age 37 years, 47% male, median disease duration 4.7 years], 229 [56%] experienced immunomodulator failure [39 required surgery, 24 experienced a new stricture, 44 experienced a new fistula/abscess, 122 required biologic escalation] with a median time to failure of 16 months. Independent predictors of treatment failure included raised C-reactive protein [CRP], low albumin, complex disease behaviour, younger age, and baseline steroids. Highest CRP and lowest albumin measured within the 3 months preceding immunomodulator initiation outperformed baseline measurements. After model selection, only highest CRP and lowest albumin remained and the resultant Crohn's Immunomodulator CRP-Albumin [CICA] index demonstrated robust optimism-corrected discriminative performance at 12, 24, and 36 months (area under the curve [AUC] 0.84, 0.83, 0.81, respectively). CONCLUSIONS: The derived CICA index based on simple, widely available markers is feasible, internally valid, and has a high utility in predicting immunomodulator failure. This requires external, prospective validation.

Thiopurines vs methotrexate: Comparing tolerability and discontinuation rates in the treatment of inflammatory bowel disease.

BACKGROUND: There are safety concerns regarding immunomodulators (thiopurines and methotrexate) for treatment of inflammatory bowel disease (IBD). AIM: To compare the long-term tolerability, and persistence of thiopurine and methotrexate therapy in IBD. METHODS: A retrospective cohort study was performed at two hospitals between 1 January 2004 and 31 December 2016 for patients commenced on thiopurines or methotrexate for IBD. Treatment discontinuation rates, intolerances and disease activity were obtained from medical records. RESULTS: There were 782 patients commenced on immunomodulator therapy; 244 (31%) on methotrexate with folate (67% subcutaneous therapy) and 538 (69%) on thiopurine (73% azathioprine). Median follow-up was 42 vs 47 months (P = 0.09). In patients on thiopurines, median 6-TGN was 298 pmol/8 x 108 RBCs, while the median dose of methotrexate was 25 mg weekly. Methotrexate recipients had a higher rate of prior immunomodulator intolerance, were typically older and had a longer disease duration (54% vs 3%, median 43 vs 36 years, 6 vs 5 years, respectively, each P < 0.05). Overall, 208 (27%) discontinued therapy due to adverse events, (40% on methotrexate vs 19% on thiopurines, P < 0.001), including nausea (18% vs 4%), fatigue (7% vs 2%) and hepatotoxicity (8% vs 2%, each P < 0.001). Hospitalisations from adverse events (0.8% vs 0.9%) and serious infections (9% vs 12%), and deaths (1% vs 0%) were comparable between groups (all P > 0.05). Discontinuation due to adverse events occurred later in patients on methotrexate than on thiopurines (median 7 vs 5 months, P = 0.08). CONCLUSION: Discontinuation of methotrexate occurred at rates twice that of dose-optimised thiopurine therapy.

The effects of COVID-19 on IBD prescribing and service provision in a UK tertiary centre.

BACKGROUND: To quantify the effects of COVID-19 on our inflammatory bowel disease (IBD) unit, including service provision, prescribing practices and use of therapeutic drug monitoring (TDM). METHODS: We performed a single centre retrospective observational cohort study. Data was extracted from our IBD database, electronic patient records and radiology/endoscopy reporting systems between 16/3/20-17/4/20 and the corresponding period in 2019. RESULTS: A similar number of patients commenced biologic therapy before COVID-19 (n = 37) and during the pandemic (n = 36). Patients in the pre-COVID-19 cohort were older (median 36 vs 29 years, P = 0.009) with a longer median disease duration (9.3 vs 5.2 years, P = 0.02). During COVID-19 there was a nonsignificant increase in prescribing of vedolizumab (8/37, 22% vs 14/36, 39%, P = 0.13) and a higher proportion of patients were anti-TNF-naïve (3/17, 18% vs 18/24, 74%, P = 0.0004). There was a reduction in use of concomitant immunomodulators (22/29, 76% vs 4/34, 12%, P < 0.0001) and increased biologic use in thiopurine-naïve patients (3/37, 8% vs 15/36, 42%, P = 0.001). Use of TDM fell by 75% (240 vs 59 tests). Outpatient appointments fell by 68% and were conducted via telemedicine. MRI scanning, endoscopy, luminal surgery and inpatient numbers fell by 87%, 85%, 100% and 82% respectively. IBD Clinical Nurse Specialist and Pharmacist helpline contacts increased by 76% and 228% respectively. CONCLUSIONS: We observed prescribing differences during COVID-19, bypassing the initiation of immunomodulators and/or anti-TNF therapy in favour of vedolizumab with a reduction in immunomodulator prescribing. We also observed a rapid reorganisation of service provision, including a shift towards telemedicine and online solutions.

Can We Predict the Toxicity and Response to Thiopurines in Inflammatory Bowel Diseases?

Thiopurines are a cheap, effective treatment option in the management of inflammatory bowel disease (IBD). However, with the growing choice of targeted therapies available, as well as the well-documented toxicities of thiopurines, the role of thiopurines has been questioned. Nevertheless, given their inexpense in an era of spiraling healthcare costs, thiopurines remain an attractive option in the right patients. In the age of personalized medicine, being able to predict patients who will respond as well as those that will develop toxicity to a treatment is vital to tailoring therapy. This review will summarize the available literature with respect to predictors of response and toxicity to thiopurines in order to guide management in IBD. Specifically, toxicities addressed will include myelotoxicity, hepatotoxicity, pancreatitis, alopecia, gastrointestinal and flu-like symptoms, and complications associated with Epstein-Barr virus. While more work needs to be done to further our ability to predict both response to and side effects from therapies, pharmacogenomic research shows significant promise in its ability to personalize our use of thiopurines.

Gastric adenocarcinoma causing biliary obstruction without ductal dilatation: a case report.

INTRODUCTION: Gastric adenocarcinoma is a known complication of partial gastrectomy. Jaundice from gastric adenocarcinoma usually occurs in the setting of hepatic nodal or parenchymal metastasis. This case demonstrates an unusual level of biliary obstruction from gastric adenocarcinoma. CASE PRESENTATION: An 84-year-old Caucasian man was diagnosed as having a new gastric adenocarcinoma at the level of the gastroenteric anastomosis of a prior Billroth II gastrectomy after presenting with painless jaundice. He had a non-dilated biliary tree on radiographic imaging despite evidence of large bile duct obstruction on liver biopsy. The obstruction was managed with endoscopic wire-guided stenting of the malignant tumor. CONCLUSIONS: The unusual finding of a non-dilated biliary tree in the face of obstructive jaundice is likely to have resulted from the unusual post-surgical anatomy and hence distal level of obstruction. Endoscopic duodenal stenting is a novel method of managing obstructive jaundice in gastric adenocarcinoma.

Turmeric Induced Liver Injury: A Report of Two Cases.

Turmeric is a commonly used oral herbal supplement with purported anti-inflammatory and antineoplastic properties. It is promoted as safe, with limited reports of severe adverse effects directly related to oral turmeric thus far in the literature. Herein we report two cases of turmeric supplement induced severe hepatitis. These cases highlight the need for physicians to be aware of patients taking this common supplement and the potential risks that exist.

6-Thioguanine Nucleotide Levels Are Associated With Mucosal Healing in Patients With Crohn's Disease.

Background: Level of 6-thioguanine nucleotides (6-TGN) has been reported to be associated with clinical remission in patients with Crohn's disease (CD) receiving maintenance treatment with thiopurines. Whether 6-TGN levels are associated with mucosal healing (MH) has seldom been investigated. We aimed to assess the correlation between 6-TGN levels and MH in patients with CD. Methods: This was a retrospective, cross-sectional, observational, multicenter study of 119 patients with CD treated with thiopurines in 3 inflammatory bowel disease referral centers (France, Australia, and China) between June 2012 and April 2016. Established CD patients who underwent ileocolonoscopy during thiopurine treatment were included. MH was defined as simple endoscopic score-CD <3. Univariate and multivariable regression analyses were used to evaluate variables associated with MH. Results: The mean concentration of 6-TGN in the MH group was higher compared with that in the non-MH group (359.0 ± 226.7 pmol/8 × 108 red blood cell count [RBC] vs 277.1 ± 170.5 pmol/8 × 108 RBC; P = 0.017). The cutoff 6-TGN concentration of 397.3 pmol/8 × 108 RBC was 86.7% specific to MH, with a sensitivity of 35.3% and area under curve (AUC) of 0.631 (P = 0.010). On multivariable analysis, 6-TGN levels were associated with MH (odds ratio [OR], 3.287; 95% confidence interval [CI], 1.348-8.017; P = 0.009) whereas late initiation of AZA (longer duration from disease onset) was inversely associated with MH (OR, 0.972; 95% CI, 0.954-0.991; P = 0.004). Conclusions: Higher 6-TGN levels are independently associated with a reduced rate of endoscopically active disease and a higher rate of mucosal healing in CD patients. Prospective studies of adequate sample size are required to confirm these findings.