The accuracy of the Alvarado score in predicting acute appendicitis in the black South African population needs to be validated

Abstract

Background: The Alvarado score is the most widely used clinical prediction tool to facilitate decision-making in patients with acute appendicitis, but it has not been validated in the black South African population, which has much wider differential diagnosis than developed world populations. We investigated the applicability of this score to our local population and sought to introduce a checklist for rural doctors to facilitate early referral. Methods: We analyzed patients with proven appendicitis for the period January 2008 to December 2012. Alvarado scores were retrospectively assigned based on patients' admission charts. We generated a clinical probability score (1-4 = low, 5-6 = intermediate, 7-10 = high). Results: We studied 1000 patients (54% male, median age 21 yr). Forty percent had inflamed, nonperforated appendices and 60% had perforated appendices. Alvarado scores were 1-4 in 20.9%, 5-6 in 35.7% and 7-10 in 43.4%, indicating low, intermediate and high clincial probability, respectively. In our subgroup analysis of 510 patients without generalized peritonitis, Alvarado scores were 1-4 in 5.5%, 5-6 in 18.1% and 7-10 in 76.4%, indicating low, intermediate and high clinical probability, respectively. Conclusion: The widespread use of the Alvarado score has its merits, but its applicability in the black South African population is unclear, with a significant proportion of patients with the disease being potentially missed. Further prospective validation of the Alvarado score and possible modification is needed to increase its relevance in our setting. © 2014 Canadian Medical Association.