Retinopathy develops at similar glucose levels but higher HbA1c levels in people with black African ancestry compared to white European ancestry: evidence for the need to individualize HbA1c interpretation

L. R. Staimez, M. K. Rhee, Y. Deng, S. E. Safo, S. M. Butler, B. T. Legvold, S. L. Jackson, C. N. Ford, P. W.F. Wilson, Q. Long, L. S. Phillips

Research output: Contribution to journalArticlepeer-review


AIMS: To examine the association of HbA 1c and glucose levels with incident diabetic retinopathy according to black African or white European ancestry.

METHODS: In this retrospective cohort study of 202 500 US Veterans with diabetes (2000-2014), measures included HbA 1c , outpatient random serum/plasma glucose, and incident retinopathy [conversion from negative to ≥2 positive evaluations (ICD-9 codes), without a subsequent negative].

RESULTS: At baseline, the study population had a mean age of 59.3 years, their mean BMI was 31.9 kg/m 2 , HbA 1c level was 57 mmol/mol (7.4%) and glucose level was 8.8 mmol/l, and 77% were of white European ancestry (white individuals) and 21% of black African ancestry (black individuals). HbA 1c was 0.3% higher in black vs white individuals (P < 0.001), adjusting for baseline age, sex, BMI, estimated glomerular filtration rate (eGFR), haemoglobin, and average systolic blood pressure and glucose. Over 11 years, incident retinopathy occurred in 9% of black and 7% of white individuals, but black individuals had higher HbA 1c , glucose, and systolic blood pressure (all P < 0.001); adjusted for these factors, incident retinopathy was reduced in black vs white individuals (P < 0.001). The population incidence of retinopathy (7%) was associated with higher mean baseline HbA 1c in individuals with black vs white ancestry [63 mmol/mol (7.9%) vs 58 mmol/mol (7.5%); P < 0.001)], but with similar baseline glucose levels (9.0 vs 9.0 mmol/l; P = 0.660, all adjusted for baseline age, sex and BMI).

CONCLUSIONS: Since retinopathy occurs at higher HbA 1c levels in black people for a given level of average plasma glucose, strategies may be needed to individualize the interpretation of HbA 1c measurements.

Original languageEnglish (US)
Pages (from-to)1049-1057
Number of pages9
JournalDiabetic Medicine
Issue number6
StatePublished - Jun 1 2020

Bibliographical note

Funding Information:
This work was supported in part by the Georgia Center for Diabetes Translation Research (P30DK111024). This work was also supported in part by U.S Veterans Administration award RO1FD003527 (L.S.P.), Veterans Affairs awards HSR&D IIR 07‐138 and IK2 CX001907 (L.S.P.) and I01 CX001899 and I01 CX001737 (L.S.P. and M.K.R.), National Institute of Health (NIH) awards R21DK099716 (L.R.S., S.E.S., L.S.P. and Q.L.) DK066204 (L.S.P.), U01 DK091958 (L.S.P. and M.K.R.) and U01 DK098246 (L.S.P.), PCORI award ME‐1303‐5840 (Q.L. and S.E.S.) and a Cystic Fibrosis Foundation award PHILLI12A0 (L.S.P.). Other support includes the National Center for Advancing Translational Sciences of the NIH under award number UL1TR000454.

Funding Information:
The authors gratefully acknowledge the contributions of Ms Christine Jasien, who shared her expertise in Veterans Affairs data and informed the present work. The authors futher acknowledge the contributions of Dr. David Benkeser for statistical guidance.?L.R.S. and L.S.P. are the guarantors of the work and take full responsibility for the work as a whole, including the study design, access to data, and the decision to submit and publish the manuscript. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the US Centers for Disease Control and Prevention or the US Veterans Affairs Department.

Publisher Copyright:
© 2020 Diabetes UK

PubMed: MeSH publication types

  • Journal Article
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.


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