Determining clinical predictors to identify non-specific abdominal pain and the added value of laboratory examinations: A prospective derivation study in a paediatric emergency department.

Aim: To develop a model to discriminate non-specific abdominal pain (NSAP) from organic pain in the paediatric emergency department (PED) and evaluate the added value of laboratory markers.

Methods: Prospective cohort study in an urban French PED including all patients aged ≥4 years with abdominal pain between November 2020 and May 2021. The outcome was the discrimination between NSAP (patients coded to have only "pain" or "constipation") and organic pain (all other diagnoses) using stepwise backward multivariate logistic regression method with bootstrap resampling.

Results: The study enrolled 246 patients. Overall, 163 patients (66.2%) had NSAP. Four variables associated with organic pain: pain in the epigastric region (OR 0.48 [0.23-0.99]), worsening pain (0.57 [0.32-0.99]), pain migration (0.42 [0.17-0.99]) and vomiting (0.47 [0.26-0.84]) were integrated in a clinical model. To discriminate NSAP with a probability of 65%, model sensitivity was 71.8% (64.9-78.7), specificity was 53.0% (42.3-63.7), and the Net Benefit (NB) was 15.4%. White Blood Count and C-reactive protein results improved discriminative capacity of the model (AUC 0.708 [0.643-0.773] vs. 0.654 [0.585-0.723], p = 0.01) with a supplementary NB of 12%. Patient follow-up showed 95% diagnostic accuracy.

Conclusion: This study reveals a four-clinical predictor model with a NB of 15% in predicting NSAP. Validation studies are necessary.