Final answer:
Relative Risk Reduction (RRR) is calculated by first determining the relative risk (RR) and then using the formula RRR = 1 - RR. An example using a preventative medication shows that the RRR can indicate how a treatment can decrease the risk of developing a disease by comparing the incidences in exposed and unexposed groups.
Step-by-step explanation:
Calculating Relative Risk Reduction (RRR):
The relative risk reduction (RRR) is a measure used in epidemiology to compare the risk of a certain event occurring in two different groups. To calculate RRR, one must first determine the relative risk (RR) by dividing the incidence of the event in the exposed group by the incidence in the unexposed group. Then, RRR can be calculated using the formula: RRR = 1 - RR. If the RR of developing a disease after a certain treatment is 0.65, it means that the treatment reduces the risk by 35% (RRR = 1 - 0.65 = 0.35). For businesses and public health officials, calculating RRR can be crucial when analyzing the effectiveness of interventions on a geographical spread and how these interventions could beneficially impact health outcomes.
Take for example a study where a new preventative medication was tried on a group of 224 patients (exposed group) who had the same risk factors for a disease, and 45 patients developed the disease after four years. In a control group of 224 patients (unexposed group), 68 developed the disease after four years. The relative risk (RR) is calculated as follows:
RR = Incidence in exposed group / Incidence in unexposed group
= (45/224) / (68/224)
= 0.20 / 0.30
= 0.67
Then, the RRR is calculated by the formula:
RRR = 1 - RR
= 1 - 0.67
= 0.33
This means the new medication reduced the risk of developing the disease by 33% compared to the control group.