Modified APPEND Score for the Diagnosis of Acute Appendicitis in a New Zealand Pasifika Population.

Background: Diagnosing acute appendicitis often requires biochemical and imaging support which may not be feasible in low- and middle-income countries (LMICs). The APPEND score, developed in New Zealand, includes C-reactive protein (CRP) which in resource-limited settings, may be hindered by slow processing times. This study aims to evaluate a modified APPEND score (mAPPEND), excluding CRP for diagnosing appendicitis in a New Zealand Pasifika cohort.

Methods: This secondary analysis utilized data from two cohorts (2011 and 2017) from Middlemore Hospital, Auckland. Patients aged ≥ 15 years with right iliac fossa pain for < 7 days were included, excluding those with prior appendicectomy or generalized peritonitis. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated, and diagnostic performance was assessed using receiver operating characteristic curve analysis, comparing the area under the curve (AUC) for both scores.

Results: Among 143 Pasifika patients, the AUC for the APPEND and mAPPEND scores were comparable (0.84 vs. 0.85 respectively, p = 0.41). The mAPPEND score demonstrated high diagnostic accuracy with scores between 1 and 2 showing high sensitivity (100% and 97%) and NPV (90% and 92%), scores 4-5 showing high specificity (94% and 100%, respectively) and PPV (90% and 100%, respectively), and a score of 3 being the most efficient with a sensitivity of 82% and specificity of 71%.

Conclusion: The mAPPEND score maintains high diagnostic accuracy for appendicitis in a New Zealand Pasifika population. This modified score is a simple and viable tool in settings where CRP testing is unfeasible, supporting its use in Pacific Island countries.