Researchers Find Inadequate Levels of Thromboprophylaxis among Atrial Fibrillation Patients

According to study results presented at the 2013 American Heart Association Scientific Sessions, analysis of health claims data indicates that physicians are underprescribing anticoagulant treatment in large numbers of patients with atrial fibrillation who are at high risk of stroke and low risk of bleeding, despite improved information on estimating bleeding risk in this population.

inadequate levels of thromboprophylaxis coverage among atrial fibrillation (AF) patients who are at high risk of stroke but low bleeding risk “raise important concerns for both private and public health plan populations.”

In the summary of their findings, Winnie W Nelson, PhD, researcher at Janssen Scientific Affairs, LLC, Raritan, NJ, and colleagues noted that although oral anticoagulation can effectively reduce the risk of stroke in patients with atrial fibrillation, thromboprophylaxis also “increases the risk of a major bleeding event.”

In light of new information on estimating bleed risk in AF from recent clinical studies (eg, HAS-BLED, ATRIA), the researchers sought to evaluate stroke and bleeding risk and its impact on anticoagulant treatment patterns among a ‘real-world’ population of patients with atrial fibrillation by evaluating administrative claims data from Medicaid, Medicare and commercial insurance databases: IMS LifeLink Database (IMS), OptumInsight (Optum), MarketScan Commercial (MSComm), MarketScan Medicare Supplemental (MSMedicare), and a Medicaid database from a southern US state (Medicaid).

For the study, researchers looked at data from patients were age 18 years and older with a new or existing diagnosis of atrial fibrillation. In the study abstract, they noted that “the first observed AF diagnosis constituted the index date, with patient outcomes assessed over one year. Study measures included stroke risk (identified by CHADS₂ score), bleeding risk (identified by ATRIA score), and anticoagulant use.”

A total of 102,577 patients with AF (mean age: 56-79 years) met inclusion criteria. Patient outcomes were assessed over one year.

The authors reported that “High bleeding risk (ATRIA ≥5 points) was estimated in 19% (IMS), 13% (Optum), 4% (MSComm), 25% (MSMedicare), and 21% (Medicaid) of study patients.”

A large number (45-82%) of patients who were at higher stroke risk (CHADS₂ score greater than 2) and low bleed risk (ATRIA scores 0-3) did not receive treatment with an anticoagulant, with Medicare and Medicaid patients being the most likely not to receive treatment.

Up to half (20-54%) of patients who were at higher stroke risk and higher bleeding risk were treated with an anticoagulant. The authors also reported that “major bleed events were rare (ie, 1%) during follow-up.”

Based on these data, the authors concluded “Inadequate levels of thromboprophylaxis coverage among AF patients with high stroke risk and low bleeding risk raise important concerns for both private and public health plan populations. Further investigation on the impact of this treatment pattern on patient outcomes is warranted.”