Optimal Management of Acute Severe Ulcerative Colitis (ASUC): Challenges and Solutions

Effectiveness and safety of upadacitinib in acute severe ulcerative colitis patients from single Chinese IBD Center: a monocentric study

Upadacitinib is an oral new selective JAK1 inhibitor that has been approved for treating adult patients with moderately to severely active ulcerative colitis. However, a growing number of studies are needed on the effectiveness of upadacitinib in the treatment of acute severe ulcerative colitis. This study was mainly aimed to describe the clinical and endoscopic effectiveness of upadacitinib 45 mg in Chinese acute severe ulcerative colitis patients following eight weeks of treatment. In this study, we examined all patients with acute severe ulcerative colitis from Xijing IBD Center, Xi'an, China, with acute severe ulcerative colitis. All patients were initially given oral upadacitinib 45 mg. Clinical indicators, C-reactive protein, and erythrocyte sedimentation rates were collected. Clinical response and clinical remission were assessed using modified Mayo. Endoscopic evaluation was performed carried out using the Mayo Endoscopic Score and Ulcerative colitis endoscopic index of severity score. A total of 14 patients who received upadacitinib were included in the study period. All patients exhibited a clinical response to 45 mg upadacitinib initially. All patients completed the 8-week induction. The clinical remission rate was 28.6% after eight weeks. Two patients revealed endoscopic remission at 14.3%. The pathology improved in 50.0% of patients. The 8-week surgical resection rate was 7.1%, with the 16-week surgical resection rate being 14.3%. Adverse events included herpes simplex virus infection and increased thrombin time. The results of our study support the short-term effectiveness and safety of upadacitinib in acute severe ulcerative colitis, providing new choices for patients' treatment. However, more extended investigation needs to be performed on the long-term effectiveness and safety.

Outcomes of patients admitted with acute, severe ulcerative colitis on biologic therapy: a retrospective analysis from a tertiary referral hospital

Background

In steroid-refractory acute, severe, ulcerative colitis (ASUC), salvage medical therapy with infliximab is recommended to reduce the risk of colectomy. However, the evidence supporting this practice is based on cohorts naïve to biologics. Consequently, the management of patients on biologic or small molecule therapy (BST) with ASUC is not well defined.

Methods

We conducted a retrospective chart review of patients admitted with ASUC to Mount Sinai Hospital (MSH) in Toronto, Ontario from January 2018 until January 2022. Included subjects were considered to be on BST if they had received a dose of these agents within 56 days prior to admission. Our outcomes of interest included the mean difference in hospital length of stay (HLOS), rates of surgical consultation, rates of inpatient colectomies, and 90-day readmission rates between the 2 groups.

Results

Of the 185 admissions for ASUC, 76 were on BST prior to admission and 109 were not. Baseline characteristics were similar between the 2 groups. There were no significant differences in hospital length of stay (7.46 days vs 7.45 days P = .52) or in-hospital colectomy rates between the 2 groups. Patients on BST had higher rates of surgical consultation (36.8% vs 8.3% P < .01) and 90-day readmission rates (26.3% vs 13.8% P = .03).

Conclusions

We did not identify significant differences in the majority of our outcomes between the 2 groups. However, patients on BST were more likely to receive a surgical consultation during their admission and had higher rates of readmission at 90 days. Further studies evaluating the underlying factors that contribute to readmission in patients on BST in hospitals are needed.

Gastroenterology Clinic Follow-Up Reduces Gastroenterology-Specific Readmissions Among Patients With Severe Ulcerative Colitis

BACKGROUND AND AIMS

Readmission within 30 days occurs in up to 18% of admitted patients with ulcerative colitis (UC). The importance of postdischarge follow-up with a gastroenterologist as well as the optimal follow-up interval is unknown.

METHODS

We conducted a retrospective cohort study of patients with UC who were admitted to Stanford University Hospital between 2010 and 2020. We included adult patients with UC who were admitted for a UC flare. Patients with a colectomy during hospitalization or with Clostridium difficile infection at the index hospitalization were excluded. The primary outcome was time to readmission for a gastroenterology (GI) indication, and the primary predictor (time dependent) was follow-up with a GI provider. Patients were followed for 180 days after discharge. Data were analyzed using a Cox proportional hazards model.

RESULTS

Of the 223 patients hospitalized with UC during the study period, 25% (n = 57) were readmitted within 180 days, with 13.9% occurring within 30 days. Early follow-up (within 7 days) was observed in 29% (n = 65) of patients, while 30-day follow-up was seen in 68.7% (n = 153), and follow-up within 180 days was seen in 198 (89%) patients. In the adjusted Cox proportional hazards model, GI follow-up was associated with fewer readmissions (hazard ratio, 0.42; 95% confidence interval, 0.22-0.81; P = .009). Early follow-up was strongly associated with a reduced risk of readmission (hazard ratio, 0.24; 95% 95% confidence interval, 0.09-0.69; P = .008). Follow-up in 7 days was associated with fewer readmissions (P < .0001).

CONCLUSIONS

Outpatient GI follow-up after UC hospitalization reduces readmissions, with the greatest reduction occurring among patients followed up within 1 week of discharge.

Management of ulcerative colitis in Taiwan: consensus guideline of the Taiwan Society of Inflammatory Bowel Disease updated in 2023

Ulcerative colitis (UC) is a chronic inflammation of the gastrointestinal tract and is characterized by alternating periods of inflammation and remission. Although UC incidence is lower in Taiwan than in Western countries, its impact remains considerable, demanding updated guidelines for addressing local healthcare challenges and patient needs. The revised guidelines employ international standards and recent research, emphasizing practical implementation within the Taiwanese healthcare system. Since the inception of the guidelines in 2017, the Taiwan Society of Inflammatory Bowel Disease has acknowledged the need for ongoing revisions to incorporate emerging therapeutic options and evolving disease management practices. This updated guideline aims to align UC management with local contexts, ensuring comprehensive and context-specific recommendations, thereby raising the standard of care for UC patients in Taiwan. By adapting and optimizing international protocols for local relevance, these efforts seek to enhance health outcomes for patients with UC.

Current Management of Acute Severe Ulcerative Colitis: New Insights on the Surgical Approaches

Acute severe ulcerative colitis (ASUC) is a life-threatening medical emergency with considerable morbidity. Despite recent advances in medical IBD therapy, colectomy rates for ASUC remain high. A scoping review of published articles on ASUC was performed. We collected data, such as general information of the disease, diagnosis and initial assessment, and available medical and surgical treatments focusing on technical aspects of surgical approaches. The most relevant articles were considered in this scoping review. The management of ASUC is challenging; currently, personalized treatment for it is unavailable. Sequential medical therapy should be administrated, preferably in high-volume IBD centers with close patient monitoring and indication for surgery in those cases with persistent symptoms despite medical treatment, complications, and clinical worsening. A total colectomy with end ileostomy is typically performed in the acute setting. Managing rectal stump is challenging, and all individual and technical aspects should be considered. Conversely, when performing elective colectomy for ASUC, a staged surgical procedure is usually preferred, thus optimizing the patients' status preoperatively and minimizing postoperative complications. The minimally invasive approach should be selected whenever technically feasible. Robotic versus laparoscopic ileal pouch-anal anastomosis (IPAA) has shown similar outcomes in terms of safety and postoperative morbidity. The transanal approach to ileal pouch-anal anastomosis (Ta-IPAA) is a recent technique for creating an ileal pouch-anal anastomosis via a transanal route. Early experiences suggest comparable short- and medium-term functional results of the transanal technique to those of traditional approaches. However, there is a need for additional comparative outcomes data and a better understanding of the ideal training and implementation pathways for this procedure. This manuscript predominantly explores the surgical treatment of ASUC. Additionally, it provides an overview of currently available medical treatment options that the surgeon should reasonably consider in a multidisciplinary setting.

Uphill battle: Innovation of thiopurine therapy in global inflammatory bowel disease care

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract that encompasses two major conditions: Crohn's disease (CD) and ulcerative colitis (UC). Historically, IBD has been primarily reported in western countries, but over the past decades, its prevalence is rapidly increasing, especially in lower and middle-income countries (LMICs) such as India and China and also in Sub-Saharan Africa. The prevalence of IBD in LMICs has been the subject of growing concern due to the impact of access to public healthcare and the burden it places on healthcare resources. The classical thiopurines face significant challenges due to cessation of therapy in approximately half of patients within one year due to side effects or ineffectiveness. In this article, we highlight innovating thiopurine treatment for IBD patients in downregulating side effects and improving efficacy.

Prevalence and risk factors for early medical and surgical complications following an admission for acute severe ulcerative colitis

Background

Risk factors for colectomy following an episode of acute severe ulcerative colitis (ASUC) have been well studied, but data examining the early complications following an episode is limited.

Objectives

We aimed to evaluate the prevalence and risk factors for medical and surgical complications within 90 days of an ASUC admission and determine if a high-intensity induction infliximab dose is associated with these complications.

Design

Retrospective analysis.

Methods

We conducted a retrospective study of ASUC admissions between January 2015 and July 2021 at a tertiary hospital. The primary outcome was the prevalence of total, medical and surgical complications within 90 days following an ASUC admission. Multivariate linear regression analysis assessed for factors associated with the prevalence of complications.

Results

A total of 150 patients had 186 hospital admissions for ASUC. In total, 101/186 (54.3%) admissions required rescue medical therapy. Standard infliximab induction occurred in 65/100 admissions, accelerated infliximab induction in 35/100 and cyclosporine in 1/100 of admissions. In total, 117 complications, including 74/117 (63.2%) medical and 43/117 (36.8%) surgical complications, arose. Low serum albumin was independently associated with a higher incidence of total [β = -0.08 (95% confidence interval (CI): -0.15, -0.01), p = 0.03] and surgical complications [β = -0.1 (95% CI: -0.18, -0.001), p = 0.047], while an increased age was associated with increased incidence of surgical complications [β = 0.06 (95% CI: 0.01, 0.12), p = 0.02]. A higher Charlson score was associated with increased medical complications [β = 0.12 (95% CI: 0.01, 0.24), p = 0.03]. Infliximab induction dose intensity was not associated with an increased incidence of any complications.

Conclusion

Early complications following an ASUC admission is prevalent although the majority are not serious. Risk factors associated with complications include low serum albumin, older age and a higher comorbidity score. Induction infliximab dose intensity, however, is not a risk factor.

The current role of Tofacitinib in acute severe ulcerative colitis in adult patients: A systematic review

BACKGROUND

Despite rescue therapy, acute severe ulcerative colitis (ASUC) is associated with a high risk of colectomy, while treatment options remain limited. Tofacitinib, a rapidly acting Janus Kinase (JAK) inhibitor, is gaining ground as an effective alternative treatment option for the management of acute severe ulcerative colitis, which may prevent emergency colectomy.

METHODS

A systematic literature search of PubMed and Embase was undertaken for studies of adult patients with ASUC treated with tofacitinib.

RESULTS

In total, two observational studies, seven case series and five case reports incorporating 134 patients who received tofacitinib in ASUC were identified with a follow-up period ranging from 30 days to 14 months. Overall, the pooled colectomy rate was 23.9% (95% CI 16.6-31.2). The pooled 90-day and 6-month colectomy free rate were 79.9% (95% CI 73.1-86.7) and 71.6% (95% CI 64-79.2) respectively. The most frequent adverse event was C. Difficile infection.

CONCLUSIONS

Tofacitinib appears to be a promising option for the treatment of ASUC. Randomized clinical trials are required to further access the efficacy, safety and optimal dose of tofacitinib in cases of ASUC.

Emergency colectomy for massive rectal bleeding in a patient with well-controlled ulcerative colitis receiving Vedolizumab

Ulcerative colitis (UC) is a chronic inflammatory condition, with a relapsing-remitting course. The case presented poses some valid questions regarding short-term and long-term management of patients with UC, and if the outcome (colectomy) could have been delayed or even prevented. Rectal bleeding is a cardinal symptom in patients with UC and it occurs among all patients during active disease. Massive rectal bleeding is an uncommon, but serious, complication of UC accounting for 0.1-1.4% of admissions. It is, nonetheless, noteworthy that instances of acute significant lower gastrointestinal bleeding accompanied by hemodynamic instability are infrequent. The rate of colectomy appears to be positively impacted by biological treatment. However, a refractory condition is still the primary reason for surgery, indicating a pressing need for new treatment approaches. Here we present the case of a young male patient who developed massive rectal bleeding and underwent emergent colectomy with ileostomy while having clinical and biological remission (normal calprotectin levels) at week 10 of Vedolizumab treatment.

Restorative pouch surgery following proctocolectomy for inflammatory bowel disease: past experience and future direction

Major advancements in surgery for patients suffering proctocolitis from ulcerative colitis (UC) or selected patients with Crohn's disease (CD) have emerged in a relatively short time. Historically, patients underwent a proctocolectomy with end ileostomy, however, a restorative proctocolectomy with an ileal pouch-anal anastomosis (IPAA) was introduced in the late 1970s in the United Kingdom and gave patients the opportunity to avoid a permanent stoma. Initially designed as a hand-sewn "S" shaped pouch, with the invention of the linear stapler, a "J" shaped pouch was described in Japan, and subsequent advances in the United States largely contributed to the pelvic pouch's evolution to the standard of care in the management of patients with inflammatory bowel disease (IBD). The procedure was then divided into different stages depending on the medical condition of the patient and minimally invasive techniques (laparoscopic & robotic surgery) have continued to advance the success of the operation. Unfortunately, pouch complications occur, and seem to be occurring at an increasing frequency with the adoption of minimally invasive surgery. The field of reoperative pouch surgery has emerged to offer patients the opportunity to restore their quality of life (QOL) without the need for a permanent ostomy. Many patients with signs of pouch failure such as pouchitis, fistulae, pain and obstruction are diagnosed with Crohn's of the pouch, but many have mechanical complications that can be corrected with surgery, rather than offering pouch excision with a permanent ostomy (continent or traditional). Patients with Crohn's may be offered an IPAA but they will not have success if they, like patients with UC, have mechanical complications leading to their pouch failure. Patients who undergo reoperative pouch surgery do well with an acceptable QOL.

Quality of Life in Patients with Acute Severe Ulcerative Colitis: Long-Term Follow-Up Results from the CONSTRUCT Trial

BACKGROUND

there is currently limited research examining the QoL of patients with Ulcerative colitis (UC) following treatment of acute severe colitis (ASUC).

OBJECTIVE

to examine the long-term QoL of ASUC patients enrolled in the CONSTRUCT trial following treatment of UC with infliximab or ciclosporin and to compare the differences in the QoL between the two drug treatments over time.

METHODS

The CONSTRUCT trial examined the cost and clinical effectiveness of infliximab and ciclosporin treatments for acute severe UC. We collected QoL questionnaire data from patients during the active trial period up to 36 months. Following trial completion, we contacted patients postannually for up to a maximum of 84 months. We collected QoL data using a disease-specific (CUCQ, or CUCQ+ for patients who had colectomy surgery) or generic (EQ5D-3L) questionnaire. We analysed QoL scores to determine if there was any difference over time and between treatments in generic or disease-specific QoL.

RESULTS

Following initial treatment with infliximab and ciclosporin, patients experienced a statistically significant improvement in both the generic and disease-specific QoL at three months. Generic scores remained fairly static for the whole follow-up period, reducing only slightly up to 84 months. Disease-specific scores showed a much sharper improvement up to 2 years with a gradual reduction in QoL up to 84 months. Generic and disease-specific QoL remained higher than baseline values. There was no significant difference between treatments in any of the QoL scores.

CONCLUSIONS

Both infliximab and ciclosporin improve QoL following initial treatment for ASUC. QoL scores remain higher than at admission up to 84 months post-treatment.

Saudi Arabia consensus guidance for the diagnosis and management of adults with inflammatory bowel disease

Optimal management of inflammatory bowel disease (IBD) relies on a clear understanding and tailoring evidence-based interventions by clinicians in partnership with patients. This article provides concise guidelines for the management of IBD in adults, based on the most up-to-date information at the time of writing and will be regularly updated. These guidelines were developed by the Saudi Ministry of Health in collaboration with the Saudi Gastroenterology Association and the Saudi Society of Clinical Pharmacy. After an extensive literature review, 78 evidence-and expert opinion-based recommendations for diagnosing and treating ulcerative colitis and Crohn's disease in adults were proposed and further refined by a voting process. The consensus guidelines include the finally agreed on statements with their level of evidence covering different aspects of IBD diagnosis and treatment.

Evidence-based pathogenesis and treatment of ulcerative colitis: A causal role for colonic epithelial hydrogen peroxide

In this comprehensive evidence-based analysis of ulcerative colitis (UC), a causal role is identified for colonic epithelial hydrogen peroxide (H₂O₂) in both the pathogenesis and relapse of this debilitating inflammatory bowel disease. Studies have shown that H₂O₂ production is significantly increased in the non-inflamed colonic epithelium of individuals with UC. H₂O₂ is a powerful neutrophilic chemotactic agent that can diffuse through colonic epithelial cell membranes creating an interstitial chemotactic molecular “trail” that attracts adjacent intravascular neutrophils into the colonic epithelium leading to mucosal inflammation and UC. A novel therapy aimed at removing the inappropriate H₂O₂ mediated chemotactic signal has been highly effective in achieving complete histologic resolution of colitis in patients experiencing refractory disease with at least one (biopsy-proven) histologic remission lasting 14 years to date. The evidence implies that therapeutic intervention to prevent the re-establishment of a pathologic H₂O₂ mediated chemotactic signaling gradient will indefinitely preclude neutrophilic migration into the colonic epithelium constituting a functional cure for this disease. Cumulative data indicate that individuals with UC have normal immune systems and current treatment guidelines calling for the suppression of the immune response based on the belief that UC is caused by an underlying immune dysfunction are not supported by the evidence and may cause serious adverse effects. It is the aim of this paper to present experimental and clinical evidence that identifies H₂O₂ produced by the colonic epithelium as the causal agent in the pathogenesis of UC. A detailed explanation of a novel therapeutic intervention to normalize colonic H₂O₂, its rationale, components, and formulation is also provided.

Pharmacokinetic and gut microbiota analyses revealed the effect of Lactobacillus acidophilus on the metabolism of Olsalazine in ulcerative colitis rats

Olsalazine is a typical 5-aminosalicylic acid (5-ASA) drug that depends on gut microbiota to liberate its anti-inflammatory moiety 5-ASA in the treatment of ulcerative colitis (UC). In recent decades, 5-ASA drugs combined with probiotics have achieved a better effective treatment for UC. Mechanisms of combination therapy have been widely discussed from a pharmacodynamic perspective. However, it is still unclear whether the better therapeutic efficacy of combination therapy was made by changing the metabolism of 5-ASA drugs in the colon under the regulation of probiotics. In the present study, combined with pharmacokinetic and gut microbiota analyses, we systematically evaluated the potential effect of Lactobacillus acidophilus (L. acidophilus) on the metabolism of Olsalazine at three levels (pharmacokinetic characteristics, metabolic microbiota, and metabolic enzymes) to offer some insights into this issue. As pharmacokinetic results showed, L. acidophilus barely had an influence on the pharmacokinetic parameters of Olsalazine, 5-ASA, and N-Ac-5-ASA. Notably, the colonic exposure of 5-ASA was not affected by L. acidophilus. Gut microbiota results also illustrated that L. acidophilus did not change the total abundance of azoreductase (azoR) and N-acetyltransferase (NAT) associated gut microbiota and enzymes, which are involved in the metabolism of Olsalazine. Both pharmacokinetic and gut microbiota results revealed that L. acidophilus did not increase the colonic exposure of 5-ASA to improve the efficacy of combination therapy. L. acidophilus played its role in UC treatment by regulating gut microbiota composition and amino acid, phenolic acid, oligosaccharide, and peptidoglycan metabolic pathways. There was no potential medication risk of combination therapy of Olsalazine and L. acidophilus. In summary, this research provided strong evidence of medication safety and a comprehensive understanding of therapeutic advantages for combination therapy of probiotics and 5-ASA drugs from the pharmacokinetic and gut microbiota perspectives.

Tofacitinib to Treat Severe Acute Refractory Colitis in a Teenager: Case Report and Review of the Literature

Acute severe colitis (ASC) may occur within 3 months of ulcerative colitis diagnosis in 9%-15% of children and the rate of colectomy is up to 40%-50% within 5 years after an ASC. The aim of this publication is to present recent and relevant data on the success of medical treatment with tofacitinib in ASC.

Methods

We report a challenging case of a teenage boy with ASC at diagnosis and conduct a discussion after a review of the literature regarding the use of tofacitinib in inflammatory bowel disease, especially in pediatric patients and in ASC.

Results

The patient was hospitalized for 10 weeks and was refractory to conventional therapies: intravenous corticosteroids, infliximab, methotrexate, and vedolizumab. He received 7 blood transfusions and also presented with a severe malnutrition requiring a total parenteral nutrition. Tofacitinib was considered as a medical last resort before colectomy and was started at week 8. Thirteen days after starting tofacitinib, he was asymptomatic and was discharged on tofacitinib as sole treatment. By week 9 of tofacitinib, a colonoscopy showed both endoscopic and histological remission. He has remained in clinical remission at 6-month follow-up.

Conclusions

Tofacitinib may be an alternative medical treatment to avoid colectomy in ASC. It is a small molecule with a rapid onset and few severe adverse events. It has been used for ASC in adult patients, allowing to avoid colectomy in more than 60%. To our knowledge, this is one of the few pediatric patients with refractory ASC at initial diagnosis who responded to tofacitinib.

Multi-utility of therapeutic drug monitoring in inflammatory bowel diseases

Inflammatory bowel disease (IBD) treatment targets have progressed over time from clinical response to clinical and endoscopic remission. Several data have shown a positive correlation between serum biologic drug concentrations and favorable therapeutic outcomes. Therapeutic drug monitoring (TDM) has evolved as an important approach for optimizing the use of immunobiologics, especially antitumor necrosis factor therapy, in patients with IBD. The use of TDM is supported by medical societies and IBD experts in different contexts; however, challenges remain due to knowledge gaps that limit the widespread use of it. The aim of this review is to assess the role of TDM in IBD, focusing on the implementation of this strategy in different scenarios and demonstrating the multi-utility aspects of this approach in clinical practice.

Fecal Calprotectin Is a Predictor of Need for Rescue Therapy in Hospitalized Severe Colitis

BACKGROUND

Up to one-third of patients hospitalized for acute severe colitis secondary to inflammatory bowel diseases (IBD) do not adequately respond to intravenous steroids. There is an unmet need to identify a useful predictor for rescue treatment in this cohort of patients.

AIMS

The aim of this study was to assess the predictive efficacy of fecal calprotectin in identifying the need for medical or surgical therapy in patients with acute severe colitis.

METHODS

We conducted a multicenter retrospective cohort study including patients with ulcerative colitis (UC) who were hospitalized for severe exacerbation of colitis. The primary outcome was the need for in-hospital medical or surgical rescue therapy. Univariate and multivariate logistic regression was performed to identify predictors of rescue therapy.

RESULTS

Our study included 147 patients with UC. One-third (33%) required rescue therapy, and 13% underwent colectomy. Patients requiring rescue therapy had significantly higher fecal calprotectin (mean 1748 mcg/g vs 1353 mcg/g, P = .02) compared with those who did not. A fecal calprotectin >800 mcg/g independently predicted the need for inpatient medical rescue therapy (odds ratio, 2.61; 95% CI, 1.12-6.12). An admission calprotectin >800 mcg/g independently predicted surgery within 3 months (odds ratio, 2.88; 95% CI, 1.01-8.17).

CONCLUSIONS

Fecal calprotectin levels may serve as a useful noninvasive predictor of medical and surgical risk in individuals with UC presenting with acute severe colitis. This approach can facilitate earlier therapeutic interventions and improve outcomes.

Therapeutic Drug Monitoring of Biologics in IBD: Essentials for the Surgical Patient

Despite significant development in the pharmacological treatment of inflammatory bowel diseases (IBD) along with the evolution of therapeutic targets and treatment strategies, a significant subset of patients still requires surgery during the course of the disease. As IBD patients are frequently exposed to biologics at the time of abdominal and perianal surgery, it is crucial to identify any potential impact of biological agents in the perioperative period. Even though detectable serum concentrations of biologics do not seem to increase postoperative complications after abdominal procedures in IBD, there is increasing evidence on the role of therapeutic drug monitoring (TDM) in the perioperative setting. This review aims to provide a comprehensive summary of published studies reporting the association of drug concentrations and postoperative outcomes, postoperative recurrence (POR) after an ileocolonic resection for Crohn’s disease (CD), colectomy rates in ulcerative colitis (UC), and perianal fistulizing CD outcomes in patients treated with biologics. Current data suggest that serum concentrations of biologics are not associated with an increased risk in postoperative complications following abdominal procedures in IBD. Moreover, higher concentrations of anti-TNF agents are associated with a reduction in colectomy rates in UC. Finally, higher serum drug concentrations are associated with reduced rates of POR after ileocolonic resections and increased rates of perianal fistula healing in CD. TDM is being increasingly used to guide clinical decision making with favorable outcomes in many clinical scenarios. However, given the lack of high quality data deriving mostly from retrospective studies, the evidence supporting the systematic application of TDM in the perioperative setting is still inconclusive.