Test Strategies to Predict Inflammatory Bowel Disease Among Children With Nonbloody Diarrhea.

OBJECTIVES: We evaluated 4 diagnostic strategies to predict the presence of inflammatory bowel disease (IBD) in children who present with chronic nonbloody diarrhea and abdominal pain. METHODS: We conducted a prospective cohort study including 193 patients aged 6 to 18 years who underwent a standardized diagnostic workup in secondary or tertiary care hospitals. Each patient was assessed for symptoms, C-reactive protein (>10 mg/L), hemoglobin (<-2 SD for age and sex), and fecal calprotectin (≥250 µg/g). Patients with rectal bleeding or perianal disease were excluded because the presence of these findings prompted endoscopy regardless of their biomarkers. Primary outcome was IBD confirmed by endoscopy or IBD ruled out by endoscopy or uneventful clinical follow-up for 6 months. RESULTS: Twenty-two of 193 (11%) children had IBD. The basic prediction model was based on symptoms only. Adding blood or stool markers increased the AUC from 0.718 (95% confidence interval [CI]: 0.604-0.832) to 0.930 (95% CI: 0.884-0.977) and 0.967 (95% CI: 0.945-0.990). Combining symptoms with blood and stool markers outperformed all other strategies (AUC 0.997 [95% CI: 0.993-1.000]). Triaging with a strategy that involves symptoms, blood markers, and calprotectin will result in 14 of 100 patients being exposed to endoscopy. Three of them will not have IBD, and no IBD-affected child will be missed. CONCLUSIONS: Evaluating symptoms plus blood and stool markers in patients with nonbloody diarrhea is the optimal test strategy that allows pediatricians to reserve a diagnostic endoscopy for children at high risk for IBD.

Predicting inflammatory bowel disease in children with abdominal pain and diarrhoea: calgranulin-C versus calprotectin stool tests.

OBJECTIVE: Calgranulin-C (S100A12) is a new faecal marker of inflammation that is potentially more specific for inflammatory bowel disease (IBD) than calprotectin, since it is only released by activated granulocytes. We compared calgranulin-C and calprotectin to see which of the two tests best predicted IBD in children with chronic abdominal pain and diarrhoea. DESIGN: Delayed-type cross-sectional diagnostic study. SETTING AND PATIENTS: Previously undiagnosed patients aged 6-17 years, who were seen in paediatric clinics in the Netherlands and Belgium, sent in a stool sample for analysis. Patients with a high likelihood of IBD underwent upper and lower endoscopy (ie, preferred reference test), while those with a low likelihood were followed for 6 months for latent IBD to become visible (ie, alternative reference test). We used Bayesian modelling to correct for differential verification bias. MAIN OUTCOME MEASURES: Primary outcome was the specificity for IBD using predefined test thresholds (calgranulin-C: 0.75 µg/g, calprotectin: 50 µg/g). Secondary outcome was the test accuracy with thresholds based on receiver operating characteristics (ROC) analysis. RESULTS: IBD was diagnosed in 93 of 337 patients. Calgranulin-C had significantly better specificity than calprotectin when predefined thresholds were used (97% (95% credible interval (CI) 94% to 99%) vs 71% (95% CI 63% to 79%), respectively). When ROC-based thresholds were used (calgranulin-C: 0.75 µg/g, calprotectin: 400 µg/g), both tests performed equally well (specificity: 97% (95% CI 94% to 99%) vs 98% (95% CI 95% to 100%)). CONCLUSIONS: Both calgranulin-C and calprotectin have excellent test characteristics to predict IBD and justify endoscopy. TRIAL REGISTRATION NUMBER: NCT02197780.

Clinical Utility of Fecal Calprotectin Monitoring in Asymptomatic Patients with Inflammatory Bowel Disease: A Systematic Review and Practical Guide.

BACKGROUND: In asymptomatic patients with inflammatory bowel disease (IBD), "monitoring" involves repeated testing aimed at early recognition of disease exacerbation. We aimed to determine the usefulness of repeated fecal calprotectin (FC) measurements to predict IBD relapses by a systematic literature review. METHODS: An electronic search was performed in Medline, Embase, and Cochrane from inception to April 2016. Inclusion criteria were prospective studies that followed patients with IBD in remission at baseline and had at least 2 consecutive FC measurements with a test interval of 2 weeks to 6 months. Methodological assessment was based on the second Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) checklist. RESULTS: A total of 1719 articles were identified; 193 were retrieved for full text review. Six studies met eligibility for inclusion. The time interval between FC tests varied between 1 and 3 months. Asymptomatic patients with IBD who had repeated FC measurements above the study's cutoff level had a 53% to 83% probability of developing disease relapse within the next 2 to 3 months. Patients with repeated normal FC values had a 67% to 94% probability to remain in remission in the next 2 to 3 months. The ideal FC cutoff for monitoring could not be identified because of the limited number studies meeting inclusion criteria and heterogeneity between selected studies. CONCLUSIONS: Two consecutively elevated FC values are highly associated with disease relapse, indicating a consideration to proactively optimize IBD therapy plans. More prospective data are necessary to assess whether FC monitoring improves health outcomes.

Avoid Endoscopy in Children With Suspected Inflammatory Bowel Disease Who Have Normal Calprotectin Levels.

In children with suspected inflammatory bowel disease, adding calprotectin stool testing to the screening strategy has been recommended to distinguish organic from nonorganic disease. In this cohort study with historical controls, we could not confirm that screening with stool calprotectin improves the diagnostic yield (ratio inflammatory bowel disease-positive endoscopies and total number of endoscopies); however, in patients with normal fecal calprotectin levels (<50 µg/g) endoscopic and histological abnormalities were not seen. We propose to refrain from endoscopy when stool calprotectin levels are normal.