No Racial Differences in the Association of Glycated Hemoglobin WithKidneyDisease and Cardiovascular Outcomes

OBJECTIVEdThere is debate regarding the clinical significance of well-established racial differences in HbA1c. We compared the associations of diabetes diagnostic categories for HbA1c and fasting glucose with clinical outcomes in black and white persons in the community. RESEARCHDESIGNANDMETHODSdWe conducted a prospective cohort analysis of participants without diabetes or cardiovascular disease from the Atherosclerosis Risk in Com-munities study.We examined the associations of clinical categories of HbA1c (,5.7%, 5.7–6.4%, $6.5%) and fasting glucose (,100, 100–125, $126 mg/dL) with outcomes separately among 2,484 black and 8,593 white participants and tested for race interactions. RESULTSdBaseline characteristics differed significantly in blacks compared with whites, in-cluding HbA1c (5.8 vs. 5.4%; P, 0.001). During 18 years of follow-up, there were trends of increased risk of kidney disease, fatal and nonfatal coronary heart disease, and stroke across categories of HbA1c in both blacks and whites. The adjusted hazard ratios for each outcome across categories of HbA1c were similar in blacks and whites (P for interaction.0.05) except for all-cause mortality. Patterns of association were similar, but weaker, for fasting glucose. HbA1c and fasting glucose both were more strongly associated with all-cause mortality in whites com