absolute risk increase


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Absolute Risk Increase

The increase in the likelihood of an event’s occurrence when a population is exposed to a determined factor—e.g., a particular toxin or other hazard, pathogen, therapy, etc.—as compared to a control population not exposed to the factor of interest.

absolute risk increase

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ARI

A measure of the negative effect of an intervention or treatment in a clinical trial. It consists of the number of adverse events found in the experimental group, minus the number of adverse events in the control group. It is the opposite of the “absolute benefit increase.”
References in periodicals archive ?
Absolute risk increases included 3.8 events per 1,000 participant years for all cause mortality, 1.4 events per 1,000 participant years for ischaemic heart disease, and 6.6 events per 1,000 participant years for chronic kidney disease.
The risk of serious adverse events was significantly higher (absolute risk increase =1.3%; number needed to harm [NNH]=78) in the pooled estimate as well as the rofecoxib study, but not in the celecoxib study.
Calcium channel blockers were associated with more nonfatal myocardial infarctions (RR=1.177; 95% CI, 1.011-1.370; absolute risk increase [ARI]=0.5%; number needed to harm [NNH]=200) and total myocardial infarctions (RR=1.182; 95% CI, 1.036-1.349; ARI=0.6%; NNH=167) compared with betablockers or diuretics.
Calcium channel blockers provided more reduction in the risk of stroke than the older antihypertensive agents (absolute risk reduction [ARR]=13.5%, P <.03; number needed to treat [NNT]=7) but were associated with an increase in risk of fatal and nonfatal MI (absolute risk increase [ARI]=19.2%, P <.01; number needed to harm [NNH]=5).
The absolute risk increase in these trials was 4.7 per 1000, which translates to a number needed to harm of 213.
For adolescents, the NNH is 1 in 92 for use of antidepressants and 1 in 556 for depression diagnosis." Kritsotakis asks, "Do any of these absolute risk increases counterweight the benefits from birth control?"