Factors Associated with Missed Appendicitis Diagnosis

Prashant Mahajan, MD, MPH, MBA

Women with comorbidities are more likely to have a missed appendicitis diagnosis when they present at the emergency department, according to recent study findings.

Prashant Mahajan, MD, MPH, MBA, and a team of investigators studied data of more than 123,000 patients diagnosed with appendicitis to better understand the factors associated with a potentially missed diagnosis of appendicitis in the emergency department for both children and adults. The findings highlighted opportunities for improvement and identified factors that could alert physicians and mitigate the risk of missed diagnosis, including women and patients who experienced abdominal pain accompanied by constipation.

Mahajan, from the Department of Emergency Medicine at University of Michigan, Ann Arbor, and colleagues analyzed patients who went to the emergency department with undifferentiated symptoms associated with appendicitis between 2010-2017. The team used a deidentified administrative claims database that captured all emergency department, outpatient, and inpatient encounters of >75 million commercially insured individuals. The database included enrollment data; demographic characteristics; individual-level insurance claims; a subset of laboratory test results; hospital discharge information; and pharmacy claims.

The investigators used ICD-9-CM and ICD-10-CM codes to identify adults >18 years old and children <18 years old who were diagnosed with appendicitis. Next, they identified emergency department visits for patients who arrived at the emergency department with isolated or combinations of undifferentiated symptoms commonly associated with appendicitis—abdominal pain, constipation, diarrhea, fever, and nausea/vomiting&mdash;in the 0-30 days before diagnosis.

A missed diagnosis was defined as an index visit where the patient presented with any 1 undifferentiated symptom or combination of symptoms linked with appendicitis where the patient wasn’t diagnosed on the same day the symptoms presented but received a subsequent diagnosis within 30 days of the initial visit. The primary outcome was the potentially missed appendicitis diagnosis.

Among the 123,711 patients eligible, 101,375 (81.9%) were adults and 22,336 (18.1%) were children. More than half (51.2%) were women with a mean age of 44.3 years old. Of the children, 43.1% were girls with a mean age of 12.2 years old.

Overall, 5.7% met the criteria for a potentially missed diagnosis of appendicitis—6% of adults and 4.4% of children. The same-day diagnosis group comprised 94% of adults and 95.6% of children.

Those in the potentially missed group were older (mean age, 50.2 years old vs 43.9 years old; P <.001) and more likely to be women (3884 patients [64.1%] vs 48,039 patients [50.4%]; P <.001) compared to patients in the same-day group.

Patients who had isolated abdominal pain (adults, AOR, .65; 95% CI, .62-.69; P <.001; children, AOR, .79; 95% CI, .69-.9; P <.001) or abdominal pain and nausea/vomiting (adults, AOR, .9; 95% CI, .84-.97; P = .003; children, AOR, .84; 95% CI, .71-.98; P = .03) were less likely to have a missed diagnosis. What’s more, a missed appendicitis diagnosis was less likely for adults who had computed tomographic scans at the first visit (abdominal pain, AOR, .58; 95% CI, .52-.65; nausea/vomiting, AOR, .63; 95% CI, .52-.75; fever, AOR, .41; 95% CI, .29-.58; diarrhea, AOR, .83; 95% CI, .58-1.2; and constipation, AOR, .60; 95% CI, .39-.94).

If a patient had abdominal pain and constipation (adults, AOR, 1.51; 95% CI, 1.31-1.75; P <.001; children, AOR, 2.43; 95% CI, 1.86-3.17; P <.001), they were more likely to have a missed appendicitis diagnosis. Undifferentiated symptoms in women including abdominal pain (AOR, 1.68; 95% CI, 1.58-1.78); nausea/vomiting (AOR, 1.68; 95% CI, 1.52-1.85); fever (AOR, 1.32; 95% CI, 1.1-1.59); diarrhea (AOR, 1.19; 95% CI, 1.01-1.4); and constipation (AOR, 1.5; 95% CI, 1.24-1.82) were also more likely to have a missed diagnosis.

Girls with abdominal pain, nausea and/or vomiting, fever, diarrhea, or constipation were more likely to have a missed diagnosis of appendicitis. Patients with comorbidity index of >2 or greater were also more likely to have their diagnosis missed.

Investigators suggested that population-based estimates of the rates of missed appendicitis diagnosis could lead to improvements and mitigate the risk of such an incident occurring.

The study, “Factors Associated With Potentially Missed Diagnosis of Appendicitis in the Emergency Department,” was published online in JAMA Network Open.