Variable Descriptions
Comorbidities were identified using ICD-9 Clinical
Modification diagnosis codes (Table 1).
Measurements
of stroke risk were based on the CHADS
18
and
CHA
2
DS
-VASc scoring systems.
Using the CHADS
system, each patient was assignedgestive heart failure (CHF), presence of hypertension (ie,
systolic blood pressure [BP] >160 mm Hg), age ≥75 years,
and presence of diabetes. Two points were assigned for a
history of stroke or transient ischemic attack (TIA).
1 point for each of the following factors: presence of con-