TABLE 4. Frequency of Appendicitis and Predictive Values of US in the Diagnosis of Appendicitis in Patients Complaining of Pain in the Lower Right Part of the Abdomen
Randomization Arm Percentage of Patients with Appendicitis* Positive Predictive Value (%){dagger} Negative Predictive Value (%){dagger}
Female patients
 Morphine 40.2 (41) 52.9 72.6
 Placebo 27.2 (25) 39.6 89.7
 Difference 13.3 (-0.6, 27.2) -17.1{ddagger} (-27.8, -6.4)
Male patients
 Morphine 57.5 (42) 80.0 69.7
 Placebo 64.4 (47) 77.1 60.0
 Difference 2.9 (-10.4, 16.2) 9.7 (-5.7, 25.1)
All patients
 Morphine 47.4 (83) 64.8 71.4
 Placebo 43.6 (72) 57.4 78.1
 Difference 7.4 (-2.9, 17.7) -6.7 (-15.9, 2.5)
* Numbers in parentheses are numbers of patients.
{dagger} Numbers in parentheses are 95% CIs.
{ddagger} P < .05 for difference between the morphine arm and placebo arm.