Prediction of Thiopurine Metabolite Levels Based on Haematological and Biochemical Parameters.

OBJECTIVES: Therapeutic drug monitoring of thiopurine erythrocyte levels is not available in all centers and it usually requires quite a long time to obtain the results. The aims of this study were to build a model predicting low levels of 6-thioguanine and 6-methylmercaptopurine in pediatric inflammatory bowel disease (IBD) patients and to build a model to predict nonadherence in patients treated with azathioprine (AZA). METHODS: The study consisted of 332 observations in 88 pediatric IBD patients. Low AZA dosing was defined as 6-thioguanine levels <125 pmol/8 × 10 erythrocytes and 6-methylmercaptopurine levels <5700 pmol/8 × 10 erythrocytes. Nonadherence was defined as undetectable levels of 6-thioguanine and 6-methylmercaptopurine <240 pmol/8 × 10 erythrocytes. Data were divided into training and testing part. To construct the model predicting low 6-thioguanine levels, nonadherence, and the level of 6-thioguanine, the modification of random forest method with cross-validation and resampling was used. RESULTS: The final models predicting low 6-thioguanine levels and nonadherence had area under the curve, 0.87 and 0.94; sensitivity, 0.81 and 0.82; specificity, 0.80 and 86; and distance, 0.31 and 0.21, respectively, when applied on the testing part of the dataset. When the final model for prediction of 6-thioguanine values was applied on testing dataset, a root-mean-square error of 110 was obtained. CONCLUSIONS: Using easily obtained laboratory parameters, we constructed a model with sufficient accuracy to predict patients with low 6-thioguanine levels and a model for prediction of AZA treatment nonadherence (web applications: https://hradskyo.shinyapps.io/6TG_prediction/ and https://hradskyo.shinyapps.io/Non_adherence/).

The Accuracy of a Home-performed Faecal Calprotectin Test in Paediatric Patients With Inflammatory Bowel Disease.

OBJECTIVES: Owing to the invasiveness of endoscopy, the use of biomarkers, especially faecal calprotectin (FC), has become standard for remission assessment. This study aimed to compare the accuracy for detection of endoscopic activity using recently developed FC home test using smartphone application (FC-IBDoc) against standard enzyme-linked immunosorbent assay (ELISA). METHODS: In all, 102 consecutive observations (89 participants) were included in prospective observational study. FC-IBDoc was performed parallelly with FC-ELISA in paediatric patients with inflammatory bowel disease indicated for endoscopy. Both tests were performed by trained staff. Mucosal healing was defined using Simple Endoscopic Score for Crohn disease (CD) ≤2 in patients with CD (n = 44), ulcerative colitis (UC) Endoscopic Index of Severity ≤4 in patients with UC (n = 27) and Rutgeerts score i0 and i1 without colon involvement in patients with CD after ileocaecal resection (n = 19). RESULTS: Out of 102 endoscopic findings 23 were assessed as mucosal healing. We found an association of the mucosal healing scores of the entire group both with FC-ELISA (P = 0.002) and FC-IBDoc (P = 0.001). The area under the receiver operating characteristic curve for FC-ELISA was 0.883 (95% confidence interval 0.807-0.960), with optimal cut-off at 136.5 µg/g. The area under the receiver operating characteristic curve for FC-IBDoc was 0.792 (95% confidence interval 0.688-0.895) with optimal cut-off at 48 µg/g. The FC-ELISA was more accurate than FC-IBDoc when tested by a Delong test (P = 0.023). CONCLUSIONS: Standard FC-ELISA for FC evaluation is more reliable predictor of mucosal healing than the FC-IBDoc in paediatric patients with inflammatory bowel disease. The cut-off values for both tests were incongruous.

Correction to: Fecal calprotectin is not a clinically useful marker for the prediction of the early nonresponse to exclusive enteral nutrition in pediatric patients with Crohn disease.

This article was originally published with all author names incorrectly listed. All author names have now been transposed and appear correctly above. The original article was corrected.

Fecal calprotectin is not a clinically useful marker for the prediction of the early nonresponse to exclusive enteral nutrition in pediatric patients with Crohn disease.

Exclusive enteral nutrition (EEN) has been recommended as the first-line therapy in children with active Crohn disease (CD). The primary aim of our study was to determine whether it is possible to use the difference between basal fecal calprotectin (F-CPT) and the value at week 2 of EEN to predict clinical response at week 6. We prospectively collected stool samples for F-CPT analysis and clinical and laboratory parameters during EEN from 38 pediatric patients (28 boys, median age 12.8 years) with newly diagnosed active luminal CD. The difference between F-CPT concentrations before EEN and at week 2 did not predict clinical non-response at week 6 (OR 0.9996 95% CI 0.9989-1.0002, p = 0.18); however, it predicted patients who did not achieve clinical remission at week 6 (OR 0.9993, 95% CI 00.9985-0.9998, p = 0.006) with sensitivity of 58%, and specificity of 92% for cut-off of F-CPT increase by 486 µg/g.Conclusions: An early decrease in F-CPT levels in children with newly diagnosed active luminal CD did not predict clinical response at week 6 of EEN induction therapy, and clinical remission was predicted with low accuracy. Therefore, F-CPT cannot be used as a predictor to select the patients in whom EEN should be terminated. What is Known: • The fecal calprotectin (F-CPT) is an important marker of intestinal inflammation. • Approximately 25% of pediatric patients with Crohn disease (CD) do not achieve clinical remission, and there is still no sufficient predictor of response to exclusive enteral nutrition (EEN) treatment. What is New: • The difference between the F-CPT concentrations before EEN treatment and at week 2 did not predict clinical response to treatment at week 6, even if it predicted clinical remission, however, with low accuracy. F-CPT is not a suitable predictor to select the patients for discontinuing of EEN induction therapy.

Low predictive value of histopathological scoring system for complications development in children with Crohn's disease.

OBJECTIVES: In pediatric Crohn's disease (PCD), the benefit of microscopy in disease activity assessment and prediction of clinical outcome is, due to the focality and transmurality of the inflammation, disputable. We investigated whether histopathological scoring system predicts complications in pediatric CD and correlates with endoscopical and clinical scores. METHODS: We performed a retrospective study on 63 patients. Endoscopy in the time of diagnosis was evaluated using the Simple Endoscopic Score (SES) and histopathology with the Global Histology Activity Score, both in its original version (GHAS) and its modification (modGHAS). Pediatric Crohn's Disease Activity Index (PCDAI) was also calculated. The patients were grouped according to the presence or absence of defined complications (intraabdominal abscess or fistula, perianal fistulating disease or stricture impenetrable for endoscope or with prestenotic dilatation) during one year of follow-up, or the necessity to initiate anti-TNF treatment for persisting or relapsing active disease in the same time period. Associations were tested with Cox regression analysis. RESULTS: SES was higher in patients with complications. However, in case of GHAS, modGHAS and PCDAI we did not find any significant association with complicated course of disease. SES above 16 points was revealed as an independent risk factor for complications development in PCD, in contrary to GHAS, modGHAS and PCDAI. We demonstrated only a weak correlation between GHAS, modGHAS and SES and no correlation between the histopathological scoring systems and PCDAI. CONCLUSIONS: In conclusion, the histopathological scoring system cannot be recommended as a reliable predictor of development of complications in children with CD.