Race/ethnicity and burden of atrial fibrillation in adults with paroxysmal atrial fibrillation.

Conflicting data exist about whether race/ethnicity affects risk of atrial fibrillation (AF) but less is known about how race/ethnicity is associated with AF burden in paroxysmal AF. We identified members of Kaiser Permanente Northern and Southern California healthcare systems who underwent 14-day continuous ambulatory electrocardiographic monitoring (ZIO® XT Patch, iRhythm Technologies, Inc.) between October 2011-October 2016 and had paroxysmal AF during monitoring. Self-reported race/ethnicity, other demographics, and stroke risk factors were obtained from electronic health records. Multivariable models evaluated the association of race/ethnicity with log-transformed AF burden (i.e., percentage of analyzable time in AF). Among 1069 adults with paroxysmal AF confirmed on continuous electrocardiographic monitoring, mean age was 69.1 years, with 45% women, 4% Black, 13% Asian/Pacific Islander, and 11% Hispanic. Median AF burden was 4% (IQR:1-13%) and varied by race/ethnicity: White (3.6%), Black (1.4%), Asian/Pacific Islander (5.7%), Hispanic (2.5%). In multivariable analyses, compared to White patients, Black patients had lower AF burden (adjusted relative estimate: -58%, 95%CI:-78% to -21%), while Asian/Pacific Islander patients had higher AF burden (adjusted relative estimate: 57%, 95%CI:7% to 130%). These findings have implications about the utility of extended continuous electrocardiographic monitoring for better understanding AF and for personalizing management across diverse populations.