Patient Demographics and Clinical Characteristics
We documented demographic variables upon cohort entry and determined the
associated morbidities from the inpatient and outpatient ICD-9 and
ICD-10 diagnostic codes recorded in the three years preceding the cohort
entry.30-32 Next, we used the patients’
characteristics and associated comorbidities to calculate the
CHADS2 score (Supplementary Tables S2 and S3) and the
modified HAS-BLED score (Supplementary Tables S2 and S4). The
comorbidity burden was scored with the Charlson-Deyo Comorbidity
Index.34,35 A frailty score was also calculated from
the modified Elders Risk Assessment in the two years preceding cohort
entry.36,37 Lastly, we assessed all drug prescriptions
filled in the two weeks preceding the cohort entry.