Predictive Value of Routine WBC Count Obtained Before Discharge for Organ Space Infection in Children with Complicated Appendicitis: Results from the Eastern Pediatric Surgery Network

The objective of this study was to evaluate the clinical utility of a routine pre-discharge white blood cell count (RPD-WBC) for predicting post-discharge organ space infection (OSI) in children with complicated appendicitis.This was a multicenter study using NSQIP-Pediatric data from 14 hospitals augmented with RPD-WBC data obtained through supplemental chart review. Children with fever or surgical site infection diagnosed during the index admission were excluded. Positive predictive value (PPV) for post-discharge OSI was calculated for RPD-WBC values of persistent leukocytosis (≥9.0x103 cells per microliter), increasing leukocytosis (RPD-WBCpreoperative WBC), quartiles of absolute RPD-WBC, and quartiles of relative proportional change from preoperative WBC. Logistic regression was used to calculate predictive values adjusted for patient age, appendicitis severity, and use of post-discharge antibiotics.1264 children were included, of which 348 (27.5%) had a RPD-WBC obtained (hospital range: 0.8-100%, P0.01). Median RPD-WBC was similar between children who did and did not develop a post-discharge OSI (9.0 vs. 8.9; p=0.57), and leukocytosis was absent in 50% of children who developed a post-discharge OSI. The PPV of RPD-WBC was poor for both persistent and increasing leukocytosis (3.9% and 9.8%, respectively), and for thresholds based on the quartiles of highest RPD-WBC values (11.1, PPV: 6.4%) and greatest proportional change (32% decrease from preoperative WBC; PPV: 7.8%).Routine pre-discharge WBC data have poor predictive value for identifying children at risk for post-discharge OSI following appendectomy for complicated appendicitis.