Previously, I had commented on the risk of stroke in atrial fibrillation patients not treated with oral anticoagulants (OAC).In that commentary I quoted Dr. Overvad -"...current guidelines discrepancies also reflect the fact that the level of stroke risk among men with a score on 1 and women with a score of 2 is on the borderline of where the impact of anticoagulation treatment shifts from beneficial to harmful." His comment seems reinforced by a recent publication in Circulation.
After that commentary I became aware of a very important -and perhaps dogma changing- article published in Circulation by GR Quinn. I added an addendum to that post but the article is important enough to be highlighted in another commentary. I re-post that addendum here:
"Unfortunately I became aware of the 2016 Circulation article
by GR Quinn et al after the above commentary was published. That very
important article provides good reason to question the dogma that the
CHA2DS2-VASc scores translate to fixed stoke rate. It is generally
accepted that if a person's stroke rate is estimated to be 1-2% per year
then treatment with an OAC offers a net clinical benefit and that the
risk score clearly relates to a quantitative stroke risk, e.g. a
CHA2DS2-VASC score of 1 means the person has a risk of about 1 % per
year and a score of 2 indicates a risk of 2%.
analysis of 34 studies of patients not treated with anticoagulants
demonstrated that the stroke rate varies widely in various cohorts. For
example, with a risk score of 2, 27% of the cohorts reported a stroke
risk of less than 1% and 33% reported stroke risk greater than 2% per
year. So the correlation between risk score and stroke risk varies with
the cohort studied.The numbers from the Northern European studies formed
the basis of the alleged relationship between the CHA2DS2-VASc score
and annual stroke risk and the North American Cohort analyses indicate
significantly lower ( about 1/3 of the European rate) stroke rates for
Quoting from the authors conclusions: '
The majority of cohorts did not observe stroke rates that would indicate a
clear expected net clinical benefit for anticoagulating AF patients
with a CHA2DS2-VASc score of 1 or 2.' "
Prediction is difficult, especially the future. Neils Bohr