Differences in Hba1c among Different Ethnicities; Is it just a Matter of Mean Glycaemia?

Background: Several studies have described ethnic differences in HbA1c. Non-Caucasian patients have been found to have an higher HbA1c than the Caucasian ones. These differences have often been attributed to disparities in access to medical care or quality of the care. Objective and hypotheses: Differences in Hba1c among the ethnicities could be related not only to mean glycaemia. The aim of our study was to observe if, at the same level of mean glucose, the HbA1c of Non-Caucasian patients was higher than the Caucasian ones. Method: We enrolled patients with type 1 and 2 diabetes, who checked the glycaemia at least twice a day. From each patients’ history we chose an Hba1c value and starting from the date of that value we selected on the Diasend the three previous months. We then collected the mean glucose for this periods and matched it with the correspondent Hba1c to observe if there was a disparity in this correspondence among the different races. Results: We enrolled 227 patients from three different hospitals of London (63 black, 117 white, 24 mixed and 23 of any other ethnicity). On a mean glucose between 6.1 and 8 mmol/l the mean Hba1c for blacks was 7.33%, 7.13% for whites, 6.46% for mixed, 0 for any other; on a mean glucose between 8.1 and 10 it was 8.86% for blacks, 8.21% for whites, 7.93% for mixed and 7.61% for any others; on a mean glucose between 10.1 and 12 it was 8.74% for blacks, 8.08% for whites, 8.94% for mixed and 8.24% for any others; on a mean glucose above 12 it was 10.13% for blacks, 9.05% for whites, 9.28% for mixed and 11.23% for any others. Conclusion: Among all the patients, on a same level of mean glucose the Hba1c of blacks was higher that the other ethnicities and the higher was the mean glucose the wider was this difference.