1. Validation and Refinement of a Prediction Rule to Identify Children at Low Risk for Acute Appendicitis Kharbanda AB, Dudley NC, Bajaj L, et al; Pediatric Emergency Medicine Collaborative Research Committee of the American Academy of Pediatrics. Arch Pediatr Adolesc Med. 2012;166(8):738-744. Copyright restrictions may apply

2. Background –Appendicitis is the most common pediatric surgical emergency. –Management of children with suspected appendicitis is highly variable. –Computed tomography has high sensitivity and specificity for appendicitis. However, the negative appendectomy and perforation rates have remained persistently high. –Standardization of care through use of a clinical prediction rule could potentially lead to more efficient, cost-effective, and safe care. Objectives –To validate and potentially refine a previously derived clinical prediction rule in a multicenter cohort of children with suspected appendicitis. Copyright restrictions may apply Introduction

3. Design –Prospective, multicenter, cross-sectional study. Sample –Children aged 3-18 years with suspected appendicitis. Defined as patients undergoing laboratory analysis, surgical consultation, or radiological imaging for the purpose of diagnosing appendicitis. History of abdominal pain <96 hours. Outcomes/Analyses –Appendicitis was determined by pathology reports. –Perforated appendicitis was determined by the attending surgeon’s operative report. –For patients without an operation, telephone follow-up was conducted 2 weeks after the emergency department visit. –Test performance of the validated rule was calculated. –The clinical prediction rule was refined using recursive partitioning. Copyright restrictions may apply Methods

4. Limitations –Enrollment varied by site and occurred exclusively at pediatric centers. However, random medical record audits revealed that missed patients were similar to those enrolled. –The clinical prediction rule was derived and validated in cohorts of children with high rates of appendicitis (>30%). The results may not be able to be generalized to other clinical settings. –Patient signs and symptoms were collected at the time of enrollment and could have evolved during the course of the emergency department visit. Copyright restrictions may apply

5. Results 2625 children and adolescents were enrolled. –1018 (38.8%) had appendicitis; 275 (27.0% of those with appendicitis) had perforated appendicitis. –Negative appendectomy rate was 8.5%. Validated rule –Sensitivity: 95.5% (95% CI, 93.9%-96.7%). –Specificity: 36.3% (95% CI, 33.9%-38.9%). –Negative predictive value: 92.7% (95% CI, 90.1%-94.6%). –Positive predicative value: 48.8% (95% CI, 46.5%-51.1%). –Likelihood ratio of negative test results: 0.12 (95% CI, 0.09-0.17). Copyright restrictions may apply

6. Results Effect of hypothetical application of the Low-Risk Appendicitis Rule. ANC indicates absolute neutrophil count (to convert count to x10 9 per liter, multiply by 0.001); RLQ, right lower quadrant. Copyright restrictions may apply

7. Results Refinement of Low-Risk Appendicitis Rule for Appendicitis Copyright restrictions may apply

8. Comment Implementation of the validated rule would theoretically lead to the following: –Prevention of some unnecessary operations. 22 patients in the low-risk cohort had negative appendectomies. The negative appendectomy rate was >30% in the low-risk cohort vs 8.5% in the overall cohort. –24% reduction in the use of diagnostic imaging (CT or ultrasonography). –Missed 4.5% (95% CI, 3.4%-6.1%) of patients with appendicitis. Patients identified as low risk by the clinical decision rule may be candidates for observation or ultrasonography rather than immediate CT or surgery. Copyright restrictions may apply

9. The validated and refined clinical decision rules allow for calculation of a patient’s risk of appendicitis: –Risk of appendicitis can be estimated between 4% and 12%. –Physicians can tailor management based on their clinical suspicion and availability of resources. Incorporation of the Low-Risk Appendicitis Rule into clinical care could lead to more standardized and cost-effective health care. Copyright restrictions may apply Comment

10. If you have questions, please contact the corresponding author: –Anupam B. Kharbanda, MD, MSc, Department of Pediatric Emergency Medicine, Children’s Hospital and Clinics of Minnesota, 2525 Chicago Ave S, Minneapolis, MN 55404 (anupam.kharbanda@childrensmn.org). Funding/Support This study was supported by grant UL1 RR024156 from the National Center for Research Resources, a component of the National Institutes of Health (NIH) and NIH Roadmap for Medical Research. The Pediatric Emergency Medicine Collaborative Research Committee data center is supported in part by the Center for Clinical Effectiveness at Baylor College of Medicine and Texas Children’s Hospital. Copyright restrictions may apply Contact Information