Repeated hemoglobin A1C ordering in the VA health system

Background: Hemoglobin A1c (HbA1c) is used to assess glycemic control in patients with diabetes. While underuse of HbA1c testing has been well studied, potential overuse is poorly characterized. Methods: Our objective was to examine the frequency of HbA1c testing in an integrated delivery system. We conducted a retrospective study of administrative data of 130,538 patients with newly diagnosed diabetes receiving care in the Veterans Administration Healthcare System during 2006 and 2007 (mean age 64.1 years, 97.3% male). Our main outcome measures were the proportion of patients receiving repeat HbA1c testing within 30 and 90 days and the proportion of patients receiving more than 4 repeat tests within 12 months of their initial HbA1c. Results: Overall 8.4% of patients (N = 11,003) received at least one repeat HbA1c within 30 days of their initial test and 30.8% (N = 40,162) within 90 days. A significantly higher proportion of patients with poor diabetes control received a repeat test within 30 days (14.7%) than patients with intermediate control (9.1%) or good control (6.8%) (P < 0.01). Overall, 4.2% of patients (N = 5,468) received more than 4 repeat HbA1c tests and 0.4% received more than 6 (N = 479). In logistic regression models, receipt of more than 4 repeat HbA1c tests was more common among patients age 50-70 years (compared to younger and older patients), whites (compared to blacks and Hispanics), and patients manifesting complications of diabetes (P < 0.01 for all). Conclusion: Repeat HbA1c testing appears to occur somewhat more frequently than is warranted.