Underprescribing Leads to Thousands of Preventable Strokes Annually

A significant amount of patients diagnosed with atrial fibrillation (AF) are at an increased risk of stroke because they are not receiving recommended blood thinning medication, according to recent findings published in the Journal of the American College of Cardiology.

“Oral anticoagulation is recommended to reduce the risk of stroke associated with nonvalvular atrial fibrillation in patients at moderate to high risk of thromboembolism,” Lucas Marzec, MD, a clinical cardiac electrophysiologist at the University of Colorado and researcher with the Colorado Cardiovascular Outcomes Research Consortium in Aurora, Colorado, and colleagues wrote in their study (J Am Coll Cardiol. May 15, 2016 dx.doi.org/10.1016/j.jacc.2017.03.540).

Often, oral anticoagulants (OACs) can reduce the risk of stroke in patients with AF by roughly two-thirds. According to recent trials, a newer type of blood thinner—direct oral anticoagulant (DOAC)—was also found to be effective in preventing strokes in this patient population.

In order to better understand the overall use of OACs among patients, the researchers examined 655,000 patients identified from the National Cardiovascular Data PINNACLE Registry. According to the study, the overall use of OACs over a seven-year period only increased slightly from 52.4% to 60.7% among patients who fit the appropriate guidelines for using OACs for stroke prevention. According to the researchers, approximately four in ten AF patients who are at an increased risk for stroke are not being prescribed the appropriate medications.

Prior studies that have examined DOAC use found that patients often receive too low a dose or physicians who prescribe them are not following the appropriate dosing recommendations. Roughly 35% of patients receiving OACs are not getting the recommended amount, and based on study results, hundreds of thousands of preventable strokes are continuing to occur each year.

The researchers found that a disparity currently exists among patients who use OACs and DOACS compared to those who do not. The findings suggest that some practices used OACs in roughly 70% of their cases. Comparatively, other practices used them in as low of 10% of their cases. Meanwhile, as some clinicians adopted DOAC use in nearly 40% of cases, other practices never used them.

“We found the overall rate of use of OAC for patients with AF increased following the introduction of DOACs. DOACs were preferentially used in patients with fewer co-morbidities, lower risk of stroke, and among those previously anticoagulated with warfarin,” Dr Marzec concluded. “In addition, there was significant practice-level variation in OAC and DOAC use. Further work is needed to better define the factors associated with variation and underuse of OAC for patients with AF at high risk for stroke to inform strategies to lower the risk of stroke for patients with AF.”

In an accompanying editorial, Eric D Peterson, MD, MPH, and Sean D Pokorney, MD, discussed the strengths and weaknesses they observed in the study, including limitations that may have impacted the findings (J Am Coll Cardiol. May 15, 2017. dx.doi.org/10.1016/j.jacc.2017.03.54).

“First, the PINNICLE registry was limited to cardiology practices that actively volunteer to participate in this national quality improvement registry, and results from PINNACLE might have overestimated adoption of DOACs and overall use of OAC in nonparticipating practices,” Dr Peterson and Dr Pokorney wrote. “Second, most data in PINNACLE was abstracted from electronic health records and might not have fully captured information on patient treatment preferences or contraindications to OAC.”

They said the study also lacked socioeconomic or pharmacy benefit status on the patients, which may affect the use of the costlier DOAC for these patients.

According to the authors, further evaluation is still needed for the underlying causes for underuse of OAC in AF which includes detailed information from patients and providers. Additionally, evidence-based care needs to become more consistent, and lastly, data bases such of PINNACLE, need to continue to monitor the quality of AF stroke prophylaxis as local, regional, and national quality improvement initiatives are conducted. Most importantly, the authors say that appropriate dosing of OAC in AF patients’ needs to become national performance measures linked to public reporting and pay-for-performance.

“Effective OAC use could substantially reduce morbidity and mortality associated with AF-related strokes, as well as have a marked effect on patient quality of life and overall health care costs,” Drs Peterson and Pokorney concluded.

—Julie Gould (Mazurkiewicz)