Review article: A practical approach to persistent gastrointestinal symptoms in inflammatory bowel disease in remission.

BACKGROUND: Persistent gastrointestinal symptoms are prevalent in adult patients with inflammatory bowel disease (IBD), even when endoscopic remission is reached. These symptoms can have profound negative effects on the quality of life of affected patients and can be difficult to treat. They may be caused by IBD-related complications or comorbid disorders, but they can also be explained by irritable bowel syndrome (IBS)-like symptoms. AIMS: To provide a practical step-by-step guide to diagnose and treat persistent gastrointestinal symptoms in patients with IBD in remission via a personalised approach. METHODS: We scrutinised relevant literature on causes, diagnostics and treatment of persistent gastrointestinal symptoms (abdominal pain or discomfort, bloating, abdominal distension, diarrhoea, constipation and faecal incontinence) in patients with IBD in remission. RESULTS: A graphical practical guide for several steps in diagnosing, identifying potential triggers and adequate treatment of persistent gastrointestinal symptoms in IBD in remission is provided based on supporting literature. The first part of this review focuses on the diagnostic and treatment approaches for potential IBD-related complications and comorbidities. The second part describes the approach to IBS-like symptoms in IBD in remission. CONCLUSIONS: Persistent gastrointestinal symptoms in IBD in remission can be traced back to potential pathophysiological mechanisms in individual patients and can be treated adequately. For both IBD-related complications and comorbidities and IBS-like symptoms in IBD in remission, pharmacological, dietary, lifestyle or psychological treatments can be effective. A systematic and personalised approach is required to reduce the burden for patients, healthcare systems, and society.

Performance of Eight Infliximab Population Pharmacokinetic Models in a Cohort of Dutch Children with Inflammatory Bowel Disease.

BACKGROUND AND OBJECTIVE: Efficacy of infliximab in children with inflammatory bowel disease can be enhanced when serum concentrations are measured and further dosing is adjusted to achieve and maintain a target concentration. Use of a population pharmacokinetic model may help to predict an individual's infliximab dose requirement. The aim of this study was to evaluate the predictive performance of available infliximab population pharmacokinetic models in an independent cohort of Dutch children with inflammatory bowel disease. METHODS: In this retrospective study, we used data of 70 children with inflammatory bowel disease (443 infliximab concentrations) to evaluate eight models that focused on infliximab pharmacokinetic models in individuals with inflammatory bowel disease, preferably aged ≤ 18 years. Predictive performance was evaluated with prior predictions (based solely on patient-specific covariates) and posterior predictions (based on covariates and infliximab trough concentrations). Model accuracy and precision were calculated with relative bias and relative root mean square error and we determined the classification accuracy at the trough concentration target of ≥ 5 mg/L. RESULTS: The population pharmacokinetic model by Fasanmade was identified to be most appropriate for the total dataset (relative bias before/after therapeutic drug monitoring: -20.7%/11.2% and relative root mean square error before/after therapeutic drug monitoring: 84.1%/51.6%), although differences between models were small and several were deemed suitable for clinical use. For the Fasanmade model, sensitivity and specificity for maximum posterior predictions for the next infliximab trough concentration to be ≥ 5 mg/L were respectively 83.5% and 80% with an area under the receiver operating characteristic curve of 0.870. CONCLUSIONS: In our paediatric cohort, various models provided acceptable predictive performance, with the Fasanmade model deemed most suitable for clinical use. Model-informed precision dosing can therefore be expected to help to maintain infliximab trough concentrations in the target range.

Early infliximab trough levels in paediatric IBD patients predict sustained remission.

Background: Exposure-response studies have shown that higher infliximab concentrations are associated with better outcomes in inflammatory bowel disease. There is little agreement about the optimal time to measure infliximab levels in children. Objectives: We aimed to evaluate whether trough levels at week 6 or week 14 predict sustained remission. The secondary aim was to define target trough levels at weeks 6 and 14. Design: We used routinely collected electronic healthcare data of 70 anti-tumour necrosis factor naïve children with inflammatory bowel disease treated with a standard infliximab induction- and variable maintenance scheme. Methods: Trough levels and blood and faecal markers for disease activity were measured before every infliximab administration. Sustained remission was defined as the absence of symptoms and low inflammatory markers between weeks 26 and 52 after the start of infliximab therapy. Optimal infliximab levels at weeks 6 and 14 were determined using the receiver operating characteristic curve. Results: The median infliximab level at week 6 was not significantly higher in children who achieved sustained remission compared to those who did not (16.9 mg/L versus 12.0 mg/L; p = 0.058) but the median infliximab level at week 14 was significantly higher in those with sustained remission (7.7 mg/L versus 3.8 mg/L; p = 0.006). The area under the receiver operating characteristics curves at weeks 6 and 14 to predict sustained remission was 0.67 (95% CI 0.51-0.83) and 0.75 (95% CI 0.60-0.90), respectively. Target trough levels at weeks 6 and 14 were ⩾13.2 and ⩾6.9 mg/L, respectively. Conclusion: An infliximab measurement at week 14 with a target through level ⩾6.9 mg/L best predicted sustained remission.

Fatigue and Physical Activity Patterns in Children With Inflammatory Bowel Disease.

OBJECTIVES: Fatigue is a common symptom in children with inflammatory bowel disease (IBD). Diagnostic tests to evaluate biological causes of fatigue commonly include markers of inflammation and hemoglobin (Hb), yet functional parameters have been inadequately studied in pediatric IBD. In this study, we compared fatigued and non-fatigued children with IBD from both a biological and functional point of view. METHODS: A cross-sectional study of 104 pediatric IBD patients with mild to moderately active IBD was conducted. Fatigued children were defined as those with a Pediatric Quality of Life Inventory Multidimensional Fatigue Scale z score <-2.0. Non-fatigued children had a z score ≥-2.0. Disease-specific quality of life (measured with IMPACT-III score), C-reactive protein (CRP), fecal calprotectin (FC), hemoglobin z score (Hb z score), and physical activity tests including 6-minute walking distance z score (6MWD z score) and triaxial accelerometry (TA) were evaluated. RESULTS: Fatigued children (n = 24) had a significant lower IMPACT-III score than non-fatigued children (n = 80). Hb z scores, CRP, FC, and 6MWD z scores were not significantly different between groups. TA was performed in 71 patients. Wear time validation requirements were met in only 31 patients. Fatigued patients spent significant shorter median time in moderate-to-vigorous activity than non-fatigued patients (18.3 vs 37.3 minutes per day, P = 0.008). CONCLUSION: Biological parameters did not discriminate fatigued from non-fatigued patients. TA possibly distinguishes fatigued from non-fatigued patients; the potential association may provide a target for interventions to combat fatigue and improve quality of life.

Ferric Carboxymaltose Versus Ferrous Fumarate in Anemic Children with Inflammatory Bowel Disease: The POPEYE Randomized Controlled Clinical Trial.

OBJECTIVE: To determine whether intravenous (IV) or oral iron suppletion is superior in improving physical fitness in anemic children with inflammatory bowel disease (IBD). STUDY DESIGN: We conducted a clinical trial at 11 centers. Children aged 8-18 with IBD and anemia (defined as hemoglobin [Hb] z-score < -2) were randomly assigned to a single IV dose of ferric carboxymaltose or 12 weeks of oral ferrous fumarate. Primary end point was the change in 6-minute walking distance (6MWD) from baseline, expressed as z-score. Secondary outcome was a change in Hb z-score from baseline. RESULTS: We randomized 64 patients (33 IV iron and 31 oral iron) and followed them for 6 months. One month after the start of iron therapy, the 6MWD z-score of patients in the IV group had increased by 0.71 compared with -0.11 in the oral group (P = .01). At 3- and 6-month follow-ups, no significant differences in 6MWD z-scores were observed. Hb z-scores gradually increased in both groups and the rate of increase was not different between groups at 1, 3, and 6 months after initiation of iron therapy (overall P = .97). CONCLUSION: In this trial involving anemic children with IBD, a single dose of IV ferric carboxymaltose was superior to oral ferrous fumarate with respect to quick improvement of physical fitness. At 3 and 6 months after initiation of therapy, no differences were discovered between oral and IV therapies. The increase of Hb over time was comparable in both treatment groups. TRIAL REGISTRATION: NTR4487 [Netherlands Trial Registry].