# Hemoglobin $$A_{1c}$$ as a Predictor of Incident Diabetes

 Title: Hemoglobin $$A_{1c}$$ as a Predictor of Incident Diabetes Author: Cheng, Peiyao; Neugaard, Britta; Foulis, Philip; Conlin, Paul Richard Note: Order does not necessarily reflect citation order of authors. Citation: Cheng, Peiyao, Britta Neugaard, Philip Foulis, and Paul R. Conlin. 2011. Hemoglobin $$A_{1c}$$ as a predictor of incident diabetes. Diabetes Care 34(3): 610-615. Full Text & Related Files: 3041192.pdf (208.3Kb; PDF) Abstract: Objective: Several studies have suggested that $$HbA_{1c}$$ levels may predict incident diabetes. With new recommendations for use of $$HbA_{1c}$$ in diagnosing diabetes, many patients with $$HbA_{1c}$$ results below the diagnostic threshold will be identified. Clinicians will need to categorize risk for a subsequent diabetic diagnosis in such patients. The objective of this study was to determine the ability of $$HbA_{1c}$$ to predict the incidence of a diabetic diagnosis. Research Design and Methods: We performed a historical cohort study using electronic medical record data from two Department of Veterans Affairs Medical Centers. Patients (n = 12,589) were identified with a baseline $$HbA_{1c}$$ <6.5% between January 2000 and December 2001 and without a diagnosis of diabetes. Patients (12,375) had at least one subsequent follow-up visit. These patients were tracked for 8 years for a subsequent diagnosis of diabetes. Results: During an average follow-up of 4.4 years, 3,329 (26.9%) developed diabetes. $$HbA_{1c}$$ $$\geq$$5.0% carried a significant risk for developing diabetes during follow-up. When compared with the reference group ($$HbA_{1c}$$ <4.5%), $$HbA_{1c}$$ increments of 0.5% between 5.0 and 6.4% had adjusted odds ratios of 1.70 (5.0–5.4%), 4.87 (5.5–5.9%), and 16.06 (6.0–6.4%) (P < 0.0001). Estimates of hazard ratios similarly showed significant increases for $$HbA_{1c}$$ $$\geq$$5.0%. A risk model for incident diabetes within 5 years was developed and validated using $$HbA_{1c}$$, age, BMI, and systolic blood pressure. Conclusions: The incidence of diabetes progressively and significantly increased among patients with an $$HbA_{1c}$$ $$\geq$$5.0%, with substantially expanded risk for those with $$HbA_{1c}$$ 6.0–6.4%. Published Version: doi:10.2337/dc10-0625 Other Sources: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3041192/pdf/ Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:10304403 Downloads of this work: