Claims Data Studies of Direct Oral Anticoagulants Can Achieve Balance in Important Clinical Parameters Only Observable in Electronic Health Records.

Claims databases provide information on the effects of direct oral anticoagulants (DOACs) as used in routine care but may not contain important data on clinical characteristics, which may be captured in electronic health records (EHRs). Within a US claims database, we identified patients initiating a DOAC or warfarin between October 2010 and December 2014. Propensity score (PS) matching, 1:1, was used to balance 78 claims-defined baseline characteristics. We evaluated whether balance was achieved in patient characteristics immeasurable in the claims data study by evaluating the balance in clinical information (using absolute standardized differences (aSDs)) from linked EHR data. From a claims data cohort study of 140,187 patients, 5,935 (4.2%) were linked to EHR data. After PS matching, almost all EHR-defined patient characteristics were well balanced (aSD < 0.1). A new user active comparator design with 1:1 PS matching on many patient characteristics improved balance on clinical risk factors observed in EHRs but not in claims data.