title: False-negative and false-positive errors in abdominal pain evaluation: failure to diagnose acute appendicitis and unnecessary surgery.
abstract: OBJECTIVE
  To test the hypothesis that physician errors (failure to diagnose appendicitis at initial evaluation) correlate with adverse outcome. The authors also postulated that physician errors would correlate with delays in surgery, delays in surgery would correlate with adverse outcomes, and physician errors would occur on patients with atypical presentations.
  
  
  METHODS
  This was a retrospective two-arm observational cohort study at 12 acute care hospitals: 1) consecutive patients who had an appendectomy for appendicitis and 2) consecutive emergency department abdominal pain patients. Outcome measures were adverse events (perforation, abscess) and physician diagnostic performance (false-positive decisions, false-negative decisions).
  
  
  RESULTS
  The appendectomy arm of the study included 1, 026 patients with 110 (10.5%) false-positive decisions (range by hospital 4.7% to 19.5%). Of the 916 patients with appendicitis, 170 (18.6%) false-negative decisions were made (range by hospital 10.6% to 27.8%). Patients who had false-negative decisions had increased risks of perforation (r = 0.59, p = 0.058) and of abscess formation (r = 0.81, p = 0.002). For admitted patients, when the inhospital delay before surgery was >20 hours, the risk of perforation was increased [2.9 odds ratio (OR) 95% CI = 1.8 to 4.8]. The amount of delay from initial physician evaluation until surgery varied with physician diagnostic performance: 7.0 hours (95% CI = 6.7 to 7.4) if the initial physician made the diagnosis, 72.4 hours (95% CI = 51.2 to 93.7) if the initial office physician missed the diagnosis, and 63.1 hours (95% CI = 47.9 to 78.4) if the initial emergency physician missed the diagnosis. Patients whose diagnosis was initially missed by the physician had fewer signs and symptoms of appendicitis than patients whose diagnosis was made initially [appendicitis score 2.0 (95% CI = 1.6 to 2.3) vs 6.5 (95% CI = 6.4 to 6.7)]. Older patients (>41 years old) had more false-negative decisions and a higher risk of perforation or abscess (3.5 OR 95% CI = 2.4 to 5.1). False-positive decisions were made for patients who had signs and symptoms similar to those of appendicitis patients [appendicitis score 5.7 (95% CI = 5.2 to 6.1) vs 6.5 (95% CI = 6.4 to 6.7)]. Female patients had an increased risk of false-positive surgery (2.3 OR 95% CI = 1.5 to 3.4). The abdominal pain arm of the study included 1,118 consecutive patients submitted by eight hospitals, with 44 patients having appendicitis. Hospitals with observation units compared with hospitals without observation units had a higher "rule out appendicitis" evaluation rate [33.7% (95% CI = 27 to 38) vs 24.7% (95% CI = 23 to 27)] and a similar hospital admission rate (27.6% vs 24.7%, p = NS). There was a lower miss-diagnosis rate (15.1% vs 19.4%, p = NS power 0.02), lower perforation rate (19.0% vs 20.6%, p = NS power 0.05), and lower abscess rate (5.6% vs 6.9%, p = NS power 0.06), but these did not reach statistical significance.
  
  
  CONCLUSIONS
  Errors in physician diagnostic decisions correlated with patient clinical findings, i.e., the missed diagnoses were on appendicitis patients with few clinical findings and unnecessary surgeries were on non-appendicitis patients with clinical findings similar to those of patients with appendicitis. Adverse events (perforation, abscess formation) correlated with physician false-negative decisions.
authors.affiliation: New Britain General Hospital, New Britain, CT 06050, USA. louisgraff@home.com
authors.forename: L
authors.initials: L
authors.lastname: Graff
authors.forename: J
authors.initials: J
authors.lastname: Russell
authors.forename: J
authors.initials: J
authors.lastname: Seashore
authors.forename: J
authors.initials: J
authors.lastname: Tate
authors.forename: A
authors.initials: A
authors.lastname: Elwell
authors.forename: M
authors.initials: M
authors.lastname: Prete
authors.forename: M
authors.initials: M
authors.lastname: Werdmann
authors.forename: R
authors.initials: R
authors.lastname: Maag
authors.forename: C
authors.initials: C
authors.lastname: Krivenko
authors.forename: M
authors.initials: M
authors.lastname: Radford
mesh_terms: D015746:Abdominal Pain / Q000175:diagnosis*; D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D001064:Appendicitis / Q000175:diagnosis* / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D002983:Clinical Competence; D015331:Cohort Studies; D003237:Connecticut; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D013505:Digestive System Surgical Procedures / Q000706:statistics & numerical data; D004636:Emergency Service, Hospital / Q000592:standards*; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care; D011336:Probability; D012189:Retrospective Studies; D012307:Risk Factors; D018709:Statistics, Nonparametric; D019564:Unnecessary Procedures / Q000706:statistics & numerical data*