Dear all,
Forgot to mention that the tools developed by GRADE are able to do all this as well as including friendly interactive presentations. All this was possible partly by an EU funded project called DECIDE (http://www.decide-collaboration.eu/)
iSoF
http://isof.epistemonikos.org/#/
Explore an example here:
http://isof.epistemonikos.org/#/finding/55ddb808352a506111abe4ea
Go to the table and activate the visual overview.
GRADE decided not to include NNTs due to their shortcomings though!
Guideline Development Tool (includes the iSoF for diagnostic/screening questions and will include the general iSoF in the future)
http://gradepro.org/
Pablo
PS. A nice video about DECIDE is available at
https://www.youtube.com/watch?v=w30RunwobFI#action=share
Hi from Canada,
An extremely useful tool for calculating ARR and NNT from a pooled RR/OR is available for free online (VisualRx, by Chris Cates), at
The tool obviates the need for hand-calculations, rightly pointed out by Andrew. Plus, the tool allows you to display the results as
an icon array. I have found this tool very helpful, for my students, as well as for my colleagues, and even for patients. It also works
quite well for convincing policy-makers about the worthiness (or lack thereof) of a new versus established interventions.
Cheers,
Janet
______________________________________________
Janet Martin, PharmD, MSc(HTA&M)
Director, Medical Evidence, Decision Integrity & Clinical Impact (MEDICI)
Assistant Professor, Department of Anesthesia & Perioperative Medicine
and Department of Epidemiology & Biostatistics
Schulich School of Medicine & Dentistry, Western University
Room B3-412, 339 Windermere Road
London, ON
Canada N6A 5A5
Tel: 1-519-685-8500 x34482
>>> Pablo Alonso Coello <
[log in to unmask]> 2016/02/11 6:58 AM >>>
This might be helpful
http://www.jclinepi.com/article/S0895-4356(12)00032-7/abstract (section 8)
Also this one we published recently might be of interest
http://www.ncbi.nlm.nih.gov/pubmed/26560992
Pablo
Pablo Alonso Coello
Centro Cochrane Iberoamericano
Instituto de Investigación Biomédica (IIB Sant Pau)
CIBER Epidemiología y Salud Pública (CIBERESP)
C/ Sant Antoni Maria Claret 167 (Pabellón 18, planta cero)
08025 Barcelona | España
[log in to unmask] | Skype: tartanedo
T: (+34) 93 553 78 14 | F:
(+34) 93 553 78 09
Hi All,
Can anyone advise on calculating risk difference/absolute risk(odds) reduction (and subsequent NNT) from pooled RR/OR. I’ve seen some calculate this based on the control event rate as a product of the weighted pooled effect estimate but can’t find any lit to
support this.
A worked example to illustrate:
Treatment event rate: 32/1424 = 0.022
Control event rate: 71/1546 = 0.046
Pooled OR: 0.45
RD/ARR: 0.046*0.45 = 0.021 (or 2.1%)
Is this right or wrong or somewhere horribly fuzzy in between?
Best,
David
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