Prevalence of Hemoglobin A1c Greater Than 6.5% and 7.0% among Hospitalized Patients without Known Diagnosis of Diabetes at an Urban Inner City Hospital

Abstract

Bronx, New York, an urban county with a large low-income, immigrant and minority population, has a prevalence of diabetes that is among the highest in the United States. The aim of the study was to evaluate the utility of hemoglobin A1c (HbA1c) in identifying patients at risk for diabetes on an in-patient medical service of a hospital serving a high prevalence community. We conducted a prospective cohort study at an urban public hospital. The study included 971 patients (1132 admissions) admitted to the general medicine service over 4 months. HbA1c was measured on all patients. Records were checked for prior diagnosis of diabetes and other clinical data. Follow-up data were obtained for those with repeat HbA1c testing or glucose within 1 yr after admission. We found that 35.2% of the patients (n = 342) had an established diagnosis of diabetes. The remaining 629 patients defined the study cohort of patients without known diabetes. Mean HbA1c was 6.05 +/- 0.87%. A total of 152 patients (24%) had admission HbA1c of at least 6.5% and 62 (9.9%) had HbA1c of at least 7.0%. Fifty-five patients with HbA1c of at least 6.5% had follow-up HbA1c within 1 yr. Of those, 44 (80.0%) met the criteria for diabetes as proposed by The International Expert Committee using repeated HbA1c testing. In communities with high prevalence of diabetes, a large percentage of patients without a diagnosis of diabetes who are admitted as in-patients have HbA1c of at least 6.5% and 7.0%. Hospital-based HbA1c testing might identify patients for whom further testing is indicated to make the diagnosis of diabetes.