Background: Rates of severe hypoglycemia are higher in African Americans than in whites. We hypothesize that the elevated rate of hypoglycemic events observed in African Americans is a result of treating African Americans and whites to the same target hemoglobin A1c (hbA1c) despite established racial differences in the association between hbA1c and glucose measures.
Methods: Using de-identified patient clinical data from 2011- 2017 on 22,554 self-identified African American or white patients with type 2 diabetes from UCSF Health, we examined racial differences in the association between hbA1c and hypoglycemic events.
Results: Of the 22,554 patients (17% African American; 54% male; mean age 59.6), 275 experienced a hypoglycemic event requiring medical care; 2.20% of African Americans experienced a hypoglycemic event compared to 1.02% of whites (p<0.001). Of the 275 patients experiencing a hypoglycemic event, 102 had a last recorded hbA1c value within 90 days prior to the event. The mean hbA1c value preceding a hypoglycemic event was 7.50% for African Americans compared to 6.91% in whites (mean difference= 0.59%, 95% confidence interval: -0.38%, 1.56%, p=0.24). In models adjusted for age, sex, and duration of diabetes, the difference in hbA1c was slightly attenuated (mean difference= 0.56%, 95%CI: -0.41%, 1.52%, p=0.26).
Conclusion: In this population, African Americans were significantly more likely to experience a hypoglycemic event than whites. HbA1c values preceding the event were slightly higher in African Americans than whites; this finding was not statistically significant but statistical power was potentially limited by sample size.