Clinical outcomes in obese and normal-weight children undergoing ultrasound for suspected appendicitis

Obesity constitutes an independent predictor for a nondiagnostic screening ultrasound (US) in suspected appendicitis. Furthermore, the imaging route consisting of the screening US with a second US if necessary has a significantly lower diagnostic accuracy in the obese children (83%) than their lean counterparts (93%). However, the effect of this association on clinical outcomes in the obese population is unknown.

In children presenting to the emergency department (ED) undergoing US for suspected appendicitis, the objective was to examine if there is a significant difference in the proportions of those with a "desirable outcome" in the obese group versus their normal-weight counterparts.

This was a reanalysis of a recent prospective cohort study conducted at a tertiary care pediatric ED. A consecutive sample of 263 previously healthy children 4-17 years of age undergoing screening US for suspected appendicitis was enrolled. Study patients were divided into obese (body mass index-for-age percentiles [BMI-FAP] ≥ 85%) and normal-weight groups. The main outcome was the proportion of children with the desirable outcome in the obese and normal-weight groups. Desirable outcomes for patients with a nondiagnostic screening US were defined as either 1) nonperforated appendicitis or alternate surgical diagnosis undergoing appropriate surgical procedure within 24 hours of assessment without a computed tomography (CT) scan or 2) no appendicitis, discharged from the ED within 24 hours without a CT scan. Secondary outcomes included hospitalization, CT imaging for any reason within 30 days of initial presentation, length of hospital stay, return visits, time to and length of surgery, and complications.

Of the 263 patients, 76 (28.9%) were obese, and 187 had a normal weight. Ninety-nine children (37.6%) had appendicitis (obese = 24, normal-weight = 75). The desirable outcome was achieved in 46 (64.5%) of the obese patients versus 137 (73.3%) of the normal-weight children (95% confidence interval [CI] for the difference = -0.21 to 0.04). Compared to the normal-weight children, the obese children had similar hospitalization rates (44.7% vs. 45.5%), median length of hospital stay (20.5 hours vs. 23.0 hours), and return ED visit rates (11.8% vs. 9.1%). The median time to surgery (obese = 10.5 hours, normal-weight = 9.0 hours), complications (obese = 25%, normal-weight = 21.3%), perforations (obese = 33%, normal-weight = 31%), and length of surgery (obese 80 [±37] minutes, normal-weight 67 [±25] minutes) were also similar. The rate of CT within 30 days of initial presentation was higher in the obese compared to the normal-weight group (13/76 or 17.1% vs. 13/187 or 6.9%, 95% CI = 0.02 to 0.23).

Previously healthy obese children undergoing screening US for suspected appendicitis experienced comparable clinical outcomes to their normal-weight counterparts. However, they were three times more likely to receive a CT scan during their investigation. These results argue for continuing current practice of using the screening US in this population, followed by a CT if clinically warranted upon reexamination.