Society of Black Academic Surgeons
Negative appendectomy: a 10-year review of a nationally representative sample

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Abstract

Background

Appendectomy remains one of the most common emergency surgical procedures encountered throughout the United States. With improvements in diagnostic techniques, the efficiency of diagnosis has increased over the years. However, the entity of negative appendectomies still poses a dilemma because these are associated with unnecessary risks and costs to both patients and institutions. This study was conducted to show current statistics and trends in negative appendectomy rates in the United States.

Methods

A retrospective analysis was conducted using data from the National Inpatient Sample from 1998 to 2007. Adult patients (>18 y) having undergone appendectomies were identified by the appropriate International Classification of Diseases 9th revision codes. Patients with incidental appendectomy and those with appendiceal pathologies, also identified by relevant International Classification of Diseases 9th revision codes, were excluded. The remaining patients represent those who underwent an appendectomy without appendiceal disease. The patients then were stratified according to sex, women were classified further into younger (18–45 y) and older (>45 y) based on child-bearing age. The primary diagnoses subsequently were categorized by sex to identify the most common conditions mistaken for appendiceal disease in the 2 groups.

Results

Between 1998 and 2007, there were 475,651 cases of appendectomy that were isolated. Of these, 56,252 were negative appendectomies (11.83%). There was a consistent decrease in the negative appendectomy rates from 14.7% in 1998 to 8.47% in 2007. Women accounted for 71.6% of cases of negative appendectomy, and men accounted for 28.4%. The mortality rate was 1.07%, men were associated with a higher rate of mortality (1.93% vs .74%; P < .001). Ovarian cyst was the most common diagnosis mistaken for appendicitis in younger women, whereas malignant disease of the ovary was the most common condition mistaken for appendiceal disease in women ages 45 and older. The most common misdiagnosis in men was diverticulitis of the colon.

Conclusions

There has been a consistent decline in the rates of negative appendectomy. This trend may be attributed to better diagnostics. Gynecologic conditions involving the ovary are the most common to be misdiagnosed as appendiceal disease in women.

Section snippets

Methods

A retrospective study was conducted using data from the National Inpatient Sample (NIS) from 1998 to 2007. The NIS is the largest all-payer inpatient care database in the United States. It contains data from approximately 8 million hospital stays each year. Information during this time period contained data from up to 38 states and it is approximately a 20% stratified sample of all US community hospitals.

The inclusion criterion was patients with appendectomy defined by International

Results

In the 10-year period between 1998 and 2007, there were 475,651 cases of appendectomy that were identified. Of these, 56,252 were negative appendectomies (11.83%). Extrapolation to nationwide figures shows that there were 28,033 cases of NA in 1998 and 21,375 cases of NA in 2007. The incidence of NA in 1998 was 14.7%; this decreased steadily to a rate of 8.47% in 2007 (Fig. 1). Women accounted for the majority of the population having negative appendectomies (40,290; 71.3%) whereas men

Comments

This study shows a steady decline in the rates of NA over the past decade, and also shows that despite this decline in NA there was a corresponding decline in the rates of appendiceal perforation (Fig. 2). We also found that although women were affected disproportionately by NA, they are less likely to die. The most common discharge diagnosis for patients who underwent NA was abdominal pain in the RLQ, indicating that no abdominal pathology was found intraoperatively. Ovarian cyst was the most

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