Negative Appendectomy Rate in Urban Referral Hospitals in Tanzania: A Cross-sectional Analysis of Associated Factors

Background: Acute appendicitis (AA) has a lifetime risk of 8.3% with a consequent 23% lifetime risk of emergency appendectomy. In atypical presentation, making a clinical diagnosis is difficult, leading to a high perforation rate (PR) or misdiagnoses and high negative appendectomy rates (NAR). This study aimed to establish NAR and explore the associated factors and possible attainable solutions to reduce it in urban referral hospitals in Tanzania. Methods: This was a crosssectional study with 91 consecutive patients, aged 10 years and older undergoing appendectomy for suspected AA with histological evaluation of specimens. The study was powered to detect the NAR at 95% confidence level and 80% power. Results: The histological NAR was 38.5% and the perforation rate was 25.3%. The Alvarado score (AS) was rarely applied (6%), despite a demonstrated ability in this study to decrease the NAR by half. Females were four times more likely to undergo negative appendectomy than males. Conclusion: The NAR is clinically significant as about two out of every five patients undergoing emergency appendectomy for suspected AA do not require the procedure. The AS is underutilized despite a demonstrated ability to decrease the NAR. We recommend that the AS be incorporated in the management of patients with suspected appendicitis.