Researchers at an academic trauma center conducted a randomized clinical trial comparing 2 surgical techniques (Technique A and Technique B) for repairing a mandible fracture. They examined rates of infectious complications and rates of malocclusion (defined as misaligned dental arches on visual examination when the jaw is closed). A total of 100 patients were enrolled in the study. Outcome assessments of each patient were conducted at 2 weeks, 4 weeks, and 8 weeks after surgery. Results showed that the relative rate of infection with Technique A compared with Technique B was 0.86 with a 95% confidence interval of 0.57-1.28; the 2 techniques had similar malocclusion rates at 8 weeks after surgery. Which of the following statements most accurately represents the comparison of Technique A and Technique B in a clinical care setting?

Question

Researchers at an academic trauma center conducted a randomized clinical trial comparing 2 surgical techniques (Technique A and Technique B) for repairing a mandible fracture.  They examined rates of infectious complications and rates of malocclusion (defined as misaligned dental arches on visual examination when the jaw is closed).  A total of 100 patients were enrolled in the study.  Outcome assessments of each patient were conducted at 2 weeks, 4 weeks, and 8 weeks after surgery.  Results showed that the relative rate of infection with Technique A compared with Technique B was 0.86 with a 95% confidence interval of 0.57-1.28; the 2 techniques had similar malocclusion rates at 8 weeks after surgery.  Which of the following statements most accurately represents the comparison of Technique A and Technique B in a clinical care setting?

Quizplus · Accepted Answer

The relative risk (RR) is commonly used in cohort and experimental studies as a measure of association between a risk factor or treatment and a disease or outcome. RR is equal to the risk of an outcome or disease (eg, infection) in a group exposed to a treatment (eg, Treatment A) divided by the risk of the same outcome or disease in a group exposed to a different treatment (eg, Treatment B). RR = (risk of disease in Treatment A) / (risk of disease in Treatment B) The RR may be interpreted as follows: RR < 1.0 indicates that exposure to Treatment A is associated with a decrease in risk of disease with respect to Treatment B. RR = 1.0 (null value) indicates that there is no association between the treatments and risk of disease. RR > 1.0 indicates that exposure to Treatment A is associated with an increase in risk of disease with respect to Treatment B. The confidence interval (CI) of a RR indicates, with a certain confidence level, whether a given RR is statistically different from the null value (ie, RR = 1). A CI that includes the null value (ie, RR = 1) is not statistically significant, and a CI that excludes the null value (ie, RR = 1) is statistically significant (at that confidence level). In this study, the RR for infection among those assigned to surgery Technique A compared to those assigned to surgery Technique B is 0.86 with a 95% CI of 0.57-1.28. An RR = 0.86 indicates that exposure to surgery Technique A decreases the risk of infection. However, because the CI includes the null value (ie, RR = 1), the decrease in risk is not statistically significant. Therefore, neither surgery technique is superior at reducing infection (Choices B and C). (Choice D) The study results show that the surgery techniques have similar rates of infectious complications and malocclusion. Assuming these rates are acceptable and there are no other major complications, there is no reason to determine the surgical techniques should not be used in a clinical care setting, but further information may be useful. Educational objective: The relative risk (RR) is a measure of association: RR < 1.0 indicates a lower risk of disease in the exposed group relative to the nonexposed group; RR = 1.0 indicates no association between exposure and disease; and RR > 1.0 indicates a greater risk of disease in the exposed group relative to the nonexposed group. A confidence interval (CI) that includes the null value for an RR (ie, RR = 1) is not statistically significant, and a CI that excludes the null value (ie, RR = 1) is statistically significant.

Researchers at an Academic Trauma Center Conducted a Randomized Clinical