TABLE 1

Model Inputs

Probability FactorPoint EstimateRange
Proportion of patients with appendicitis810,1416,24290.3260.145–0.614
Ultrasound with visualized appendix, sensitivity8,9,1618,2426,30330.9860.957–1.0
Ultrasound with visualized appendix, specificity8,9,1618,2426,30330.9360.654–1.0
Proportion ultrasound that do not visualize appendix among patients with appendicitis8,9,16,18,2427,30330.1580.0172–0.394
Proportion ultrasound that do not visualize appendix among patients without appendicitis8,9,16,18,2427,30330.4660.104–0.910
Secondary signs of inflammation on ultrasound without visualized appendix, sensitivity9,16,24,27,3032,340.5340.29–1.0
Secondary signs of inflammation ultrasound without visualized appendix, specificity9,16,24,27,30320.94390.6–0.99
CT, sensitivity230.950.92–0.97
CT, specificity230.920.90–0.94
MRI, sensitivity120.9650.943–0.978
MRI, specificity120.9610.935–0.977
Proportion of patients with perforation at presentation358,15,29,30,33,360.2860.174–0.405
Proportion of patients with perforation after delayed diagnosis3,370.7740.774–0.81
Mortality, uncomplicated appendicitis36,380.00010.0001–0.0001
Mortality, perforated appendicitis36,38,390.0003470.0002–0.0004
Cost of limited abdominal ultrasound, $40,41228.61171.46–285.77a
Cost of abdominal and pelvic CT with contrast, $40,41805.55604.44–1007.40a
Cost of abdominal and pelvic MRI without contrast, $40,411160.801284.41–2140.69a
Cost of hospitalization for appendicitis without rupture, $9460.904559.69–16 010.45
Cost of hospitalization for appendicitis with rupture, $15387.105792.20–32 310.18
Cost of ED visit without imaging, $665.83499.37–832.38a
Disutility for appendicitis without ruptureb0.06240.0146–0.1509
Disutility for appendicitis with ruptureb0.08370.0149–0.2275
Disutility for ED visit42,43,b0.0170.009–0.026
  • a 75% to 125% of 2017 Medicare reimbursement.

  • b Disutility is defined as 1-utility.