Am J Cardiol. 2015 Jul 15;116(2):230-5. doi: 10.1016/j.amjcard.2015.04.012.

Effect of race on outcomes (stroke and death) in patients >65 years with atrial fibrillation.

Kabra R1, Cram P2, Girotra S3, Vaughan Sarrazin M4.
  • 1Division of Cardiology, Department of Internal Medicine, University of Tennessee Health Science Center, Memphis, Tennessee.
  • 2Department of Internal Medicine, University of Toronto, Toronto, Ontario, Canada; University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada.
  • 3Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, Iowa.
  • 4Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, Iowa. Electronic address: mary-vaughan-sarrazin@uiowa.edu.

 

Abstract

Atrial fibrillation (AF) is associated with stroke and death. We sought to determine whether there are any racial differences in the outcomes of death and stroke in patients with AF. We used Medicare administrative data from January 1, 2010, to December 31, 2011, to identify 517,941 patients with newly diagnosed AF. Of these, 452,986 patients (87%) were non-Hispanic white, 36,425 (7%) were black, and 28,530 (6%) were Hispanic. The association between race and outcomes of death and stroke were measured using Cox proportional hazard models. Over a median follow-up period of 20.3 months, blacks had a significantly higher hazard of death (hazard ratio [HR] = 1.46; 95% confidence interval [CI] 1.43 to 1.48; p <0.001) and stroke (HR = 1.66; 95% CI 1.57 to 1.75; p <0.001), compared with white patients. After controlling for pre-existing co-morbidities, the higher hazard of death in blacks was eliminated (HR 0.95; 95% CI 0.93 to 0.96; p <0.001) and the relative hazard of stroke was reduced (HR = 1.46; 95% CI 1.38 to 1.55; p <0.001). Similarly, Hispanics had a higher risk of death (HR = 1.11; 95% CI 1.09 to 1.14; p <0.001) and stroke (HR = 1.21; 95% CI 1.13 to 1.29; p <0.001) compared with whites. The relative hazard of death was lower in Hispanics (HR 0.82; 95% CI 0.80 to 0.84; p <0.001) compared with whites, after controlling for pre-existing co-morbidities, and the relative hazard of stroke was also attenuated (HR = 1.11; 95% CI 1.03 to 1.18; p <0.001). In conclusion, in patients >65 years with newly diagnosed AF, the risks of death and stroke are higher in blacks and Hispanics compared with whites. The increased risk was eliminated or significantly reduced after adjusting for pre-existing co-morbidities. AF may be a marker for underlying co-morbidities in black and Hispanic patients who may be at a higher mortality risk.

PMID: 26004053

 

SUPPLEMENT:

Atrial fibrillation (AF) is associated with up to 5-fold higher risk of stroke and up to 2 fold higher risk of death. However it is not known if the likelihood of AF-related stroke and death differ by race or ethnicity. We therefore studied whether AF is associated with different outcomes (stroke and death) by race and ethnicity.

We performed a retrospective study using Medicare administrative data for beneficiaries age 66 and older to identify patients with newly diagnosed AF from January 1, 2010 through December 31, 2011. Patients were excluded if they were < 66 years of age as they did not have 1 year of Medicare eligibility prior to AF diagnosis for assessing medical history. We studied 517,941 patients, of which 452,986 (87%) were white, 36,425 (7%) were black and 28,530 (6%) were Hispanic. The mean age was 79 years, and 40% were males. Black and Hispanic patients had significantly more co-morbidities compared to white patients, including heart failure, hypertension, prior stroke, coronary artery disease, diabetes mellitus and obesity. Blacks and Hispanics also had a higher CHA2DS2-VASc score, compared to the whites, suggesting their higher risk of having stroke with AF. The primary outcome of our study was death and the secondary outcome was stroke.

Over a mean follow up period of 20.3 months per patient, 137,271 (30%) white, 14,850 (41%) black and 9343 (33%) Hispanic patients died and 12,337 (2.7%) white, 1,504 (4.1%) black and 910 (3.2%) Hispanic patients experienced stroke. Compared to the whites, black patients with AF had a 46% higher risk of death (p<0.001) and a 66% higher risk of stroke (p<0.001). After adjusting for co-morbidities, as compared to the whites, the higher hazard of death in blacks was eliminated and the higher risk of stroke decreased to 46%. Similarly, Hispanics had 11% higher hazard of death and 21% higher risk of stroke as compared to the whites. Following adjustments for co-morbidities, the risk of death in the Hispanics decreased (HR 0.82) compared to the whites. Their risk of stroke also decreased compared to the whites (HR 1.11). These differences persisted even after adjust for anticoagulation.

Our study demonstrates that AF in patients > 65 years of age is associated with higher risk of death and stroke in blacks and Hispanics as compared to the whites. This is likely due to increased co-morbidities in the minority population. Hence, AF management in these populations should also include treatment of associated co-morbidities besides anticoagulation and rate/rhythm control for AF.

 

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