Racial Disparities Found in Anticoagulation of Atrial Fibrillation Patients in Large Cohort Analysis

In 2010, atrial fibrillation (AF) affected 2.7 million to 6.1 million Americans, with a projected increase to 12.1 million in 2030. AF prevalence among white patients is double that of black patients; however, blacks often have a higher risk of stroke than whites. Disparities in prescriptions of oral anticoagulation (OAC) have been reported in previous studies with small cohorts.

Kevin L. Thomas, MD, of Duke, presented a retrospective analysis of AF admissions recorded in the Premier Healthcare Database at the American Heart Association's Scientific Sessions held November 11 to 15, 2017, in Anaheim, CA. Christopher Granger, MD, and Bimal R. Shah, MD, of Duke were also involved in the study.

"We were fortunate to have access to the Premier Healthcare Database," Thomas said. "Unlike other studies assessing trends in OAC prescription, we were able to look at a large cohort of patients hospitalized for AF. We tried to include only patients at high risk of stroke and exclude those who would not be candidates for OAC."

Patients included in the analysis (N = 1,579,456) were admitted for AF between January 2011 and June 2015 and had a CHA₂DS₂-VASc score of at least 2. Patients were excluded from the analysis if records showed the presence of a mechanical heart valve; any bleed during admission; neurological, spinal, or cardiac surgery; death before discharge; discharge to hospice; or transfer to an acute care facility. Black patients accounted for 8.0% of AF admissions; white patients composed 81.2% of admissions.

Black patients hospitalized for AF had different demographics and a higher prevalence of noncardiovascular comorbidities than white patients. The average CHA₂DS₂-VASc scores were similar between blacks and whites at 4.5 and 4.4, respectively. However, black patients tended to be younger at a median age of 70.9 years compared with 77.2 years for white patients. Younger black patients (< 45 years) had a higher CHA₂DS₂-VASc score than similarly aged white patients at 3.0 and 2.0, respectively. Additionally, the black AF patient population included a higher percentage of women (55.7% vs 52.9% of white patients). Black patients also had a greater number of noncardiovascular comorbidities. In patients aged 45 to 84 years, the median Charlson Comorbidity Index score was 3.0 for black patients compared with 2.0 for white patients.

At discharge, black and white patients had similar rates of OAC prescription at about 46%. Aspirin was prescribed for 13% to 14% of patients. "We have certain metrics for quality of care," Thomas emphasized. "Overall, we're not getting to all the appropriate patients. Less than 50% of AF patients are leaving the hospital on anticoagulation even though all of the patients in the study had a CHA₂DS₂-VASc score of at least 2. Aspirin is not standard of care, particularly in a high-risk patient population."

Thomas and colleagues performed a logistics regression model to assess independent predictors of OAC use at discharge and adjust for differences in clinical and hospital characteristics. The model identified predictors of OAC use: a primary diagnosis of AF or a history of stroke, transient ischemic attack, or heart failure.

According to the study results, black patients were 10% less likely to be placed on OAC than white patients. Of note, when black AF patients have a stroke, the stroke tends to be more severe than that experienced by white AF patients. In addition, women were 14% less likely to be prescribed OAC at discharge than men.

Although the study did not address reasons for undertreatment of AF patients at discharge, Thomas said that the likely reasons were concerns related to falls/bleeding risk and patient adherence to treatment regimens. "Concern over falls or compliance is overstated," Thomas said. "However, we do need more evidence that demonstrates that falls are not correlated with a high incidence of life-threatening bleeding."

"It's egregious that less than half of patients discharged from the hospital are being placed on OAC," Thomas said. "It's even more egregious that a patient population that we know has higher risk is even less likely to be placed on OAC."

"Opportunities exist to improve OAC use in AF patients. We have to raise awareness of the disparities in care, and we have to train health care providers to mitigate disparities based on race, age, or gender," he concluded.

Source: Thomas KL, James RA, Marcsisin V, et al. Racial differences in patient characteristics and oral anticoagulation use at discharge among patients with atrial fibrillation. Presented at: American Heart Association Scientific Sessions 2017; November 11-15, 2017; Anaheim, CA. Abstract T2208.