Elevated HbA(1c) and Fasting Plasma Glucose in Predicting Diabetes Incidence Among Older Adults Are two better than one?

OBJECTIVE To determine which measuresimpaired fasting glucose (IFG), elevated HbA(1c), or bothbest predict incident diabetes in older adults.RESEARCH DESIGN AND METHODSFrom the Health, Aging, and Body Composition study, we selected individuals without diabetes, and we defined IFG (100-125 mg/dL) and elevated HbA(1c) (5.7-6.4%) per American Diabetes Association guidelines. Incident diabetes was based on self-report, use of antihyperglycemic medicines, or HbA(1c) 6.5% during 7 years of follow-up. Logistic regression analyses were adjusted for age, sex, race, site, BMI, smoking, blood pressure, and physical activity. Discrimination and calibration were assessed for models with IFG and with both IFG and elevated HbA(1c).RESULTSAmong 1,690 adults (mean age 76.5, 46% men, 32% black), 183 (10.8%) developed diabetes over 7 years. Adjusted odds ratios of diabetes were 6.2 (95% CI 4.4-8.8) in those with IFG (versus those with fasting plasma glucose [FPG