Pediatric negative appendectomy rate: Trend, predictors, and differentials

Background: Appendectomy is one of the most commonly performed emergency operations in children. The diagnosis of appendicitis can be quite challenging, particularly in children. We set out to determine the accuracy of diagnosis of appendicitis by analyzing the trends in the negative appendectomy rate (NAR) using a national database. Materials and Methods: Analysis of the Kids Inpatient Database (KID) was performed for the years 2000, 2003, and 2006 on children with appendectomy, excluding incidental appendectomies. Children (<18 y) without appendicitis but who underwent appendectomies were classified as negative appendectomies (NA), and those with appendicitis as positive appendectomies (PA). Comparisons were made between those with PA versus NA by demographic characteristics. The subset of patients with NA was then further analyzed. Results: An estimated 250,783 appendectomies met the inclusion criteria. The NAR was 6.7%. Length of stay (LOS) was longer in NA versus PA (7 versus 3 d, P < 0.05). The NAR was increased in children under 5 y (21.1% versus 5.4% for among the 5-10 y versus 5.9% among the >10 y, P < 0.0001) and in females (9.3% versus 5.1%, P < 0.001). On multivariate analysis, increasing age was associated with lower odds of NA (OR = 0.92, P < 0.001). Females, rural hospitals, and Blacks were significantly more likely to experience NA. Conclusions: Younger age, female gender, Black ethnicity and rural hospitals are independent predictors of NA. These factors can be incorporated into diagnostic algorithms to improve the accuracy of diagnosis of appendicitis in children.