Absolute Risk Reduction


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Absolute Risk Reduction

Epidemiology A measure of the treatment effect, comparing the probability—or mean of a type of outcome in the control group—with that of a treatment group.
EBM The absolute arithmetic difference in the risk—i.e., the rate of an adverse event or outcome—between a study (treated/experimental) population and a control population.
References in periodicals archive ?
Aspirin use, compared with no aspirin, was associated with significant reductions in the composite cardiovascular outcome of cardiovascular mortality, nonfatal myocardial infarction, and nonfatal stroke (57.1 per 10000 participant-years with aspirin and 61.4 per 1000 participant-years with no aspirin) (hazard ratio [HR], 0.89 [95% credible interval, 0.84-0.95]; absolute risk reduction, 0.38% [95% CI, 0.20%-0.55%]; number needed to treat, 265).
Again, the relative risk reduction of some 36 percent is touted, and the absolute risk reduction of less than two percent is not mentioned.
Supplementation with omega-3 PUFAs showed no significant correlation of absolute risk reduction and major cardiovascular events.
To illustrate, if ten out of 10,000 untreated people normally die from a disorder but only five die in 10,000 treated individuals, the relative risk has decreased by 50%, but the absolute risk reduction (five out of 10,000) is less impressive.
The absolute risk reduction in Michigan exceeds that in Illinois by 1.53 (3.95-2.42) releases per 100 facilities, which is 23 percent of Michigan's initial (1990-1994) average annual release rate.
This constituted an absolute risk reduction of five percent and a relative risk reduction of 14 percent in favor of CABG.
For example, in a general population of 1 million women, even a 1.6pc absolute risk reduction amounts to 16,000 fewer cases of cancer.
Absolute risk reduction was calculated at 6.6 to 11.7% of pneumonia cases.
Research by Galesic, Garcia-Retamero, and Gigerenzer (2009; see also Garcia-Retamero & Galesic, 2010b) showed that visual aids are useful when the risk information is presented both in complex numerical formats such as relative risk reduction (e.g., aspirin can reduce the risk of having a stroke or heart attack by 13% in people with symptoms of arterial disease) and in numerical formats that are relatively easy to understand (absolute risk reduction; e.g., aspirin can reduce the risk of having a stroke or heart attack from 8% to 7% in people with symptoms of arterial disease).
6b) The absolute risk reduction (ARR) states the absolute difference in the rates of events between the two groups and gives an indication of the baseline risk and treatment effect.
Absolute risk reduction or rise (ARR) The actual rate of improvement or worsening caused by an experimental intervention.