title: Body Mass Index is a Poor Predictor of Bedside Appendix Ultrasound Success or Accuracy.
abstract: BACKGROUND
  The objective of this study was to determine whether there is a relationship between body mass index (BMI) and success or accuracy rate of beside ultrasound (BUS) for the diagnosis of appendicitis.
  
  
  METHODS
  Patients four years of age and older presenting to the emergency department with suspected appendicitis were eligible. Enrollment was by convenience sampling. After informed consent, BUS was performed by trained emergency physicians who had undergone a minimum of one-hour didactic training on the use of BUS to diagnose appendicitis. We ascertained subject outcomes by a combination of medical record review and telephone follow up. Calculated BMI for adults and children were divided into four categories (underweight, normal, overweight, obese) according to Centers for Disease Control and Prevention classifications.
  
  
  RESULTS
  A total of 125 subjects consented for the study, and 116 of them had adequate image data for final analysis. Seventy (60%) of the subjects were children. Prevalence of appendicitis was 39%. Fifty-two (45%) of the BUS studies were diagnostic (successful). Overall accuracy rate was 75%. Analysis by chi-square test or Mann-Whitney U test did not find any significant correlation between BMI category and BUS success. Similarly, there was no significant correlation between BMI category and BUS accuracy. The same conclusion was reached when children and adults were analyzed separately, or when subjects were dichotomized into underweight/normal and overweight/obese categories.
  
  
  CONCLUSIONS
  BMI category alone is a poor predictor of appendix BUS success or accuracy.
authors.affiliation: Advocate Christ Medical Center, Department of Emergency Medicine, Oak Lawn, Illinois.
authors.forename: Samuel H F
authors.initials: SH
authors.lastname: Lam
authors.affiliation: Advocate Christ Medical Center, Department of Emergency Medicine, Oak Lawn, Illinois.
authors.forename: Christopher
authors.initials: C
authors.lastname: Kerwin
authors.affiliation: Advocate Christ Medical Center, Department of Emergency Medicine, Oak Lawn, Illinois.
authors.forename: P John
authors.initials: PJ
authors.lastname: Konicki
authors.affiliation: Advocate Christ Medical Center, Department of Emergency Medicine, Oak Lawn, Illinois.
authors.forename: Diana
authors.initials: D
authors.lastname: Goodwine
authors.affiliation: Advocate Christ Medical Center, Department of Emergency Medicine, Oak Lawn, Illinois.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lambert
mesh_terms: D000293:Adolescent; D000328:Adult; D001064:Appendicitis / Q000000981:diagnostic imaging*; D015992:Body Mass Index; D002648:Child; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D050177:Overweight; D019095:Point-of-Care Systems / Q000592:standards*; D011446:Prospective Studies; D015203:Reproducibility of Results; D013851:Thinness; D014463:Ultrasonography / Q000592:standards*; D014481:United States