CHADS2 Score, Stroke Risk in Atrial Fibrillation

The CHADS2 score is used to help decide whether or not to prescribe an anticoagulant for atrial fibrillation.  An approach to the decision of warfarin for oral anticoagulation for atrial fibrillation is suggested in [link url="//www.aafp.org/afp/2005/0615/afp20050615p2348-f1.pdf" memo="(link)"] Am Fam Physician. 2005 Jun 15;71(12):2348-2350. 
1) Use the [link url="../../cardiovascular/chads2/" memo="(link)"] CHADS2 rule as well as the [link url="../../cardiovascular/accp-stroke-risk-calculator/" memo="(link)"] ACCP rule to determine the risk of stroke.
2) If both these measures predict moderate risk of stroke, proceed to calculate the [link url="../../cardiovascular/outpatient-bleeding-risk-index-obri/" memo="(link)"] Outpatient Bleeding Risk Index and weigh the risks versus the benefits.
[select name="Q1" value="No (0 points)=0|YES (1 point)=1"] <-- Congestive heart failure
[select name="Q2" value="No (0 points)=0|YES (1 point)=1"] <-- Hypertension: Blood pressure consistently above 140/90 or on blood pressure medication?
[select name="Q3" value="No (0 points)=0|YES (1 point)=1"] <-- Age > 75
[select name="Q4" value="No (0 points)=0|YES (1 point)=1"] <-- Diabetes mellitus
[select name="Q5" value="No (0 points)=0|YES (2 points)=2"] <-- Prior stroke or TIA
Score --> [calc value="score=(Q1)+(Q2)+(Q3)+(Q4)+(Q5)" memo="score"] out of 6 points
Interpretation --> [calc value="score=(Q1)+(Q2)+(Q3)+(Q4)+(Q5);score>2?'5.3% annual stroke risk (high)':score>0?'2.7% annual stroke risk (moderate)':'0.8% annual stroke risk (low)'" memo="interpretation"]
[checkbox memo="display/hide references" name="footnotes" value=""][conditional field="footnotes" condition="(footnotes).is('')"]
references:  
[link url="//www.aafp.org/afp/2005/0615/p2348.html" memo="#1"] Am Fam Physician. 2005 Jun 15;71(12):2348-2350.
[link url="//www.aafp.org/afp/2010/0315/p780.html" memo="#2"] Am Fam Physician. 2010 Mar 15;81(6):780-782.[/conditional]