Racial Differences in and Prognostic Value of Biomarkers of Hyperglycemia

Abstract

Objective: We compared levels and associations of traditional (fasting glucose, HbA1c) and nontraditional (fructosamine, glycated albumin, and 1,5-anhydroglucitol [1,5-AG]) biomarkers of hyperglycemia with incident cardiovascular disease (CVD), incident end-stage renal disease (ESRD), and prevalent retinopathy in black and white adults.

Research design and methods: We included 10,373 participants without (8,096 white, 2,277 black) and 727 with diagnosed diabetes (425 white, 302 black) from the Atherosclerosis Risk in Communities (ARIC) Study. We used Cox proportional hazards models to compare hazards ratios of CVD and ESRD among blacks and whites from baseline (1990-1992) through 2012. We compared the odds ratios (from logistic regression) of retinopathy among blacks and whites. We tested for the interaction of each biomarker with race.

Results: Median values of biomarkers were higher among blacks versus whites (all P < 0.001). Relative risks for each biomarker with incident CVD and ESRD, and odds ratios for each biomarker with prevalent retinopathy, were similar by race (all P values for interaction by race >0.10).

Conclusions: The prognostic value of HbA1c, fructosamine, glycated albumin, and 1,5-AG with incident CVD, incident ESRD, and prevalent retinopathy were similar by race. Our results support similar interpretation of HbA1c and nontraditional biomarkers of hyperglycemia among black and whites with respect to long-term complications.

Figure 1

Adjusted associations of hyperglycemia with incident CVD, incident ESRD, and prevalent retinopathy by race. Hazard ratios (HRs) for CVD and ESRD were obtained using separate Cox proportional hazards regression models for white and black participants. Odds ratios for prevalent retinopathy were obtained using separate logistic regression models for white and black participants. In models that included both white and black participants, P values for interactions were calculated by conducting a likelihood ratio test to compare models with and without terms for the interaction between race and hyperglycemia. Models included adjustment for age; sex (male, female); BMI; BMI²; LDL-c; HDL-c; triglycerides; cholesterol-lowering medication use (yes, no); systolic blood pressure; antihypertensive medication use (yes, no); eGFR; family history of diabetes (yes, no); education level (less than high school, high school or some college, college or more); alcohol consumption (current, former, never); cigarette smoking status (current, former, never); and physical activity level. Categories of diabetes—no diabetes; no diabetes, intermediate levels; no diabetes, elevated levels; diabetes; and diabetes, elevated levels—were defined using the following levels of each biomarker, respectively: fasting glucose: <100, 100–125, ≥126, <149, ≥149 mg/dL; HbA_1c: <5.7, 5.7–6.4, ≥6.5, <7.0, ≥7.0%; fructosamine: <239.8, 239.8–268.6, ≥268.7, <275.7, ≥275.7 mg/dL; glycated albumin: <13.52, 13.52–15.55, ≥15.56, <16.46, ≥16.46%; 1,5-AG: ≥15.0, 7.9–14.9, <7.9, >9.2, ≤9.2 μg/mL. Gray symbols indicate results for white participants. Black symbols indicate results for black participants. DM, diabetes.