Minorities With ESRD And Afib Less Likely To Fill Prescriptions For Warfarin

Minority patients with end-stage renal disease (ESRD) and atrial fibrillation were less likely than whites to fill warfarin prescriptions, even though they were more likely to experience a stroke, researchers say.

"Clinicians caring for people on dialysis must be cognizant of the racial and ethnic disparities in treatment and outcomes associated with a diagnosis of atrial fibrillation," said Dr. Paul Kimmel of the US National Institute of Diabetes and Digestive and Kidney Diseases, in email to Reuters Health. "To improve outcomes for all people on dialysis who also have atrial fibrillation, clinicians should carefully consider the risks and benefits of each specific anticoagulation therapy for each individual patient. And in the future, carefully designed and controlled clinical trials should aim to give further understanding as to which treatment is best for which patient."

Dr. Kimmel and colleagues analyzed data on 56,587 hemodialysis patients with atrial fibrillation who were followed for 1 year.

As reported in the Journal of the American Society of Nephrology, whites accounted for 69%; blacks, 19%; Hispanics, 8%; and Asians, 3%. The number of strokes per 1,000 people was 84 for whites; 94 for blacks; 97 for Hispanics; and 102 for Asians.

Overall, compared with whites, blacks were 13% more likely to experience stroke; Hispanics, 15% more likely; and Asians, 16% more likely. However, minority patients also were less likely to fill a warfarin prescription (10%, 17%, and 28% less likely, respectively).

Analyses suggested that equalizing the warfarin distribution to that of the white population would prevent 7% of excess strokes among black patients; 10%, among Hispanics; and 12% among Asians.

No racial/ethnic disparities in all-cause mortality or use of cardiovascular disease procedures were found.

Summing up, the authors state, "Racial/ethnic disparities in all-cause stroke among hemodialysis patients with atrial fibrillation are partially mediated by lower use of anticoagulants among black, Hispanic, and Asian patients. The reasons for these disparities are unknown, but strategies to maximize stroke prevention in minority hemodialysis populations should be further investigated."

Nephrologist Dr. Naveed Ashfaq, of the Ohio State University Wexner Medical Center in Columbus, commented in an email to Reuters Health that minorities may have lesser access to healthcare due to transportation issues, which also limit the possibility of frequent and close monitoring of the international normalized ratio (INR) in warfarin clinics. In addition, minority patients face language and cultural barriers and generally have lower health literacy.

Further, with respect to warfarin specifically, he said, "African American patients require a higher dose than Caucasians to maintain a therapeutic INR."

"As clinicians, we should focus on social determinants of health before prescribing any medication," he said. "Newer anticoagulants do not require extensive, frequent and close INR monitoring. Also, (they) do not require a higher number of pills, which is common with warfarin. I think compliance can be improved with reducing pill burden and monitoring. The downside of these new anticoagulants is the cost."

—Marilynn Larkin

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