Assessment of proadrenomedullin as diagnostic or prognostic biomarker of acute appendicitis in children with acute abdominal pain.

Background: Acute appendicitis (AA) is one of the most frequent surgical pathologies in pediatrics.

Objectives: To investigate the utility of proadrenomedullin (pro-ADM) for the diagnosis of AA.

Methods: Prospective, analytical, observational, and multicenter study conducted in 6 pediatric emergency departments. Children up to 18 years of age with suspected AA were included. Clinical, epidemiological, and analytical data were collected.

Results: We studied 285 children with an average age of 9.5 years (95% confidence interval [CI], 9.1-9.9). AA was diagnosed in 103 children (36.1%), with complications in 10 of them (9.7%). The mean concentration of pro-ADM (nmol/L) was higher in children with AA (0.51 nmol/L, SD 0.16) than in children with acute abdominal pain (AAP) of another etiology (0.44 nmol/L, SD 0.14; p < 0.001). This difference was greater in complicated cases compared with uncomplicated AA (0.64 nmol/L, SD 0.17 and 0.50 nmol/L, SD 0.15, respectively; p = 0.005). The areas under the receiver-operating characteristic curves were 0.66 (95% CI, 0.59-0.72) for pro-ADM, 0.70 (95% CI, 0.63-0.76) for C-reactive protein (CRP), 0.84 (95% CI, 0.79-0.89) for neutrophils, and 0.84 (95% CI, 0.79-0.89) for total leukocytes. The most reliable combination to rule out AA was CRP ≤1.25 mg/dL and pro-ADM ≤0.35 nmol/L with a sensitivity of 96% and a negative predictive value of 93%.

Conclusion: Children with AA presented higher pro-ADM values than children with AAP of other etiologies, especially in cases of complicated AA. The combination of low values of pro-ADM and CRP can help to select children with low risk of AA.