A randomized controlled study was done to evaluate the efficacy of a novel medication in reducing severe cutaneous responses in individuals with rheumatoid arthritis treated with adalimumab. 75 persons with rheumatoid arthritis were given the new medicine in addition to adalimumab, whereas the other 75 got a placebo in addition to adalimumab. According to the findings, six individuals in the new treatment group experienced severe cutaneous responses, compared to nine in the placebo group. Which of the following best describes the new medication group's relative risk decrease for severe cutaneous reactions?

Question

Quizplus · Accepted Answer

Eductional Objective: Relative risk reduction (RRR) measures how much a given treatment reduces the risk of an unfavorable outcome relative to the control group. RRR may be defined as the difference in risk of the unfavorable outcome in the treatment group (eg, new drug) compared to the control group (eg, placebo):
RRR = (Riskcontrol - Risktreatment) / Riskcontrol
In this example, Riskcontrol (ie, risk of severe cutaneous reactions in the placebo group) is 9/75 = 0.12, and Risktreatment (ie, risk of severe cutaneous reactions in the new drug group) is 6/75 = 0.08. Therefore, RRR for severe cutaneous reactions among patients in the new drug group is:
RRR = (0.12 - 0.08) / 0.12 = 0.33
Alternately, RRR may be calculated using relative risk (RR). When using RR, the formula for RRR is:
RRR = 1 - RR
For this example, RR is the ratio of the risk of severe cutaneous reactions in the new drug group to the risk of severe cutaneous reactions in the placebo group, calculated as follows:
RR = (Risktreatment / Riskcontrol) = (0.08/0.12) = 0.67
Therefore, RRR is:
RRR = 1 - 0.67 = 0.33

A Randomized Controlled Study Was Done to Evaluate the Efficacy