Absolute risk reduction: Difference between revisions
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In clinical [[epidemiology]] and [[evidence-based medicine]], the [[absolute risk reduction]] is a measure that compares the frequency of a clinical outcome in group of patients exposed to a factor compared to a control group of patients.<ref name="pmid15313996">{{cite journal |author=Barratt A, Wyer PC, Hatala R, ''et al'' |title=Tips for learners of evidence-based medicine: 1. Relative risk reduction, absolute risk reduction and number needed to treat |journal=CMAJ |volume=171 |issue=4 |pages=353–8 |year=2004 |pmid=15313996 |doi=10.1503/cmaj.1021197 |url=http://www.cmaj.ca/cgi/pmidlookup?view=long&pmid=15313996}}</ref> This measure should be contrasted with the [[relative risk reduction]]. | In clinical [[epidemiology]] and [[evidence-based medicine]], the [[absolute risk reduction]] is a measure that compares the frequency of a clinical outcome in group of patients exposed to a factor compared to a control group of patients.<ref name="pmid15313996">{{cite journal |author=Barratt A, Wyer PC, Hatala R, ''et al'' |title=Tips for learners of evidence-based medicine: 1. Relative risk reduction, absolute risk reduction and number needed to treat |journal=CMAJ |volume=171 |issue=4 |pages=353–8 |year=2004 |pmid=15313996 |doi=10.1503/cmaj.1021197 |url=http://www.cmaj.ca/cgi/pmidlookup?view=long&pmid=15313996}}</ref> This measure should be contrasted with the [[relative risk reduction]]. | ||
Most journal articles fail to report absolute measures which may lead to exaggerated perceptions of results.<ref>Welch HG et al.Ratio measures in leading medical journals: structured review of accessibility of underlying absolute risks.BMJ. 2006 Dec 16;333(7581):1248. Epub 2006 Oct 23. PMID 17060338</ref> | |||
==Calculations== | ==Calculations== | ||
Revision as of 07:58, 15 May 2008
In clinical epidemiology and evidence-based medicine, the absolute risk reduction is a measure that compares the frequency of a clinical outcome in group of patients exposed to a factor compared to a control group of patients.[1] This measure should be contrasted with the relative risk reduction.
Most journal articles fail to report absolute measures which may lead to exaggerated perceptions of results.[2]
Calculations
| Outcome | ||||
|---|---|---|---|---|
| Present | Absent | |||
| Experimental group | Cell A | Cell B | Total in the experimental group | |
| Control group | Cell C | Cell D | Total in the control group | |
| Total with the outcome | Total without the outcome | |||
References
- ↑ Barratt A, Wyer PC, Hatala R, et al (2004). "Tips for learners of evidence-based medicine: 1. Relative risk reduction, absolute risk reduction and number needed to treat". CMAJ 171 (4): 353–8. DOI:10.1503/cmaj.1021197. PMID 15313996. Research Blogging.
- ↑ Welch HG et al.Ratio measures in leading medical journals: structured review of accessibility of underlying absolute risks.BMJ. 2006 Dec 16;333(7581):1248. Epub 2006 Oct 23. PMID 17060338