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 (,22 SD for age and sex), and fecal calprotectin ($250 mg/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.