A team from Seattle, Washington, USA, determined whether the frequency of misdiagnosis preceding appendectomy has decreased with increased availability of computed tomography, ultrasonography, and laparoscopy.
They conducted a retrospective, population-based cohort study of data from a Washington State hospital discharge database. A total of 85,790 residents were included. United States Census Bureau data for 1987-1998 was also analyzed.
The population-based incidence of appendectomy with acute appendicitis (perforated or not) or with a normal appendix was measured.
|16% of appendectomy patients were misdiagnosed.
| Journal of the American Medical Association |
Among 63,707 nonincidental appendectomy patients, 84.5% had appendicitis (25.8% with perforation) and 15.5% had no associated diagnosis of appendicitis.
After adjusting for age and sex, the population-based incidence of unnecessary appendectomy and of appendicitis with perforation did not change significantly over time.
Among women of reproductive age, the population-based incidence of misdiagnosis was found to increase 1% per year.
The incidence of misdiagnosis increased 8% yearly in patients older than 65 years. However, it did not change significantly in children younger than 5 years.
The researchers found that the proportion of patients undergoing laparoscopic appendectomy who were misdiagnosed was significantly higher than that of open appendectomy patients (19.6% vs 15.5%).
Dr David R. Flum, of the University of Washington, Seattle, said on behalf of his colleagues, "Contrary to expectation, the frequency of misdiagnosis leading to unnecessary appendectomy has not changed with the introduction of computed tomography, ultrasonography, and laparoscopy.
"The frequency of perforation has not decreased either."
"These data suggest that, on a population level, diagnosis of appendicitis has not improved with the availability of advanced diagnostic testing," he concluded.