Development and Validation of a Novel Pediatric Appendicitis Risk Calculator (pARC)

Abstract

Objectives: We sought to develop and validate a clinical calculator that can be used to quantify risk for appendicitis on a continuous scale for patients with acute abdominal pain.

Methods: The pediatric appendicitis risk calculator (pARC) was developed and validated through secondary analyses of 3 distinct cohorts. The derivation sample included visits to 9 pediatric emergency departments between March 2009 and April 2010. The validation sample included visits to a single pediatric emergency department from 2003 to 2004 and 2013 to 2015. Variables evaluated were as follows: age, sex, temperature, nausea and/or vomiting, pain duration, pain location, pain with walking, pain migration, guarding, white blood cell count, and absolute neutrophil count. We used stepwise regression to develop and select the best model. Test performance of the pARC was compared with the Pediatric Appendicitis Score (PAS).

Results: The derivation sample included 2423 children, 40% of whom had appendicitis. The validation sample included 1426 children, 35% of whom had appendicitis. The final pARC model included the following variables: sex, age, duration of pain, guarding, pain migration, maximal tenderness in the right-lower quadrant, and absolute neutrophil count. In the validation sample, the pARC exhibited near perfect calibration and a high degree of discrimination (area under the curve: 0.85; 95% confidence interval: 0.83 to 0.87) and outperformed the PAS (area under the curve: 0.77; 95% confidence interval: 0.75 to 0.80). By using the pARC, almost half of patients in the validation cohort could be accurately classified as at <15% risk or ≥85% risk for appendicitis, whereas only 23% would be identified as having a comparable PAS of <3 or >8.

Conclusions: In our validation cohort of patients with acute abdominal pain, the pARC accurately quantified risk for appendicitis.

Conflict of interest statement

POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose. The funding agencies took no part in data analysis, interpretation, or manuscript preparation. No person received any honorarium or other payment to produce this manuscript. This article was written by Dr Anupam Kharbanda, and all authors take full responsibility for the integrity of the data and the accuracy of data analysis.

Copyright © 2018 by the American Academy of Pediatrics.

Figures

FIGURE 1

Calibration plot of the pARC and PAS comparison (n = 1426).

FIGURE 2

Comparison of the pARC and PAS in the validation sample (n = 1426). The AUC for the PAS was 0.77 (95% CI: 0.75 to 0.80). The AUC for the pARC was 0.85 (95% CI: 0.83 to 0.87).

FIGURE 3

Comparison of the pARC and PAS based on predicted risk of appendicitis in the validation sample (n = 1426).