Table 2

Improvement in predictive performance for incident T2D by adding HbA1c to other covariates by cohort and race

ModelCovariatesCohort/raceAUC without HbA1c (95% CI)AUC with HbA1c (95% CI)Difference in AUC (95% CI)P
HbA1c onlyAge, sexFHS0.56 (0.53, 0.59)0.68 (0.64, 0.72)0.118 (0.076, 0.16)<0.0001
ARIC whites0.55 (0.53, 0.56)0.66 (0.65, 0.67)0.113 (0.112, 0.114)<0.0001
ARIC blacks0.55 (0.53, 0.58)0.66 (0.63, 0.68)0.106 (0.105, 0.107)<0.0001
HbA1c + fasting laboratory testsAge, sex, FG, TG, HDLFHS0.85 (0.82, 0.87)0.85 (0.83, 0.88)0.006 (−0.002, 0.014)0.15
ARIC whites0.71 (0.70, 0.72)0.73 (0.71, 0.74)0.017 (0.017, 0.017)<0.0001
ARIC blacks0.68 (0.66, 0.70)0.71 (0.67, 0.73)0.028 (0.028, 0.029)<0.0001
HbA1c + clinic visitAge, sex, FH, BMI, SBPFHS0.75 (0.72, 0.78)0.77 (0.74, 0.80)0.022 (0.005, 0.040)0.013
ARIC whites0.67 (0.65, 0.68)0.71 (0.70, 0.72)0.042 (0.042, 0.042)<0.0001
ARIC blacks0.62 (0.60, 0.65)0.68 (0.66, 0.70)0.058 (0.057, 0.059)<0.0001
HbA1c + fasting laboratory tests + clinic visitAge, sex, BMI, SBP, FH, TG, HDL, FGFHS0.86 (0.83, 0.88)0.86 (0.84, 0.89)0.004 (−0.002, 0.011)0.18
ARIC whites0.73 (0.72, 0.74)0.74 (0.73, 0.75)0.014 (0.013, 0.014)<0.0001
ARIC blacks0.70 (0.673, 0.72)0.72 (0.70, 0.74)0.022 (0.022, 0.023)0.001
  • AUC, area under the curve; FH, family history of T2D.