AUTHOR=Briker Sara M. , Aduwo Jessica Y. , Mugeni Regine , Horlyck-Romanovsky Margrethe F. , DuBose Christopher W. , Mabundo Lilian S. , Hormenu Thomas , Chung Stephanie T. , Ha Joon , Sherman Arthur , Sumner Anne E. 

TITLE=A1C Underperforms as a Diagnostic Test in Africans Even in the Absence of Nutritional Deficiencies, Anemia and Hemoglobinopathies: Insight From the Africans in America Study

JOURNAL=Frontiers in Endocrinology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2019.00533

DOI=10.3389/fendo.2019.00533

ISSN=1664-2392

ABSTRACT=<p><bold>Introduction:</bold> To improve detection of undiagnosed diabetes in Africa, there is movement to replace the OGTT with A1C. The performance of A1C in the absence of hemoglobin-related micronutrient deficiencies, anemia and heterozygous hemoglobinopathies is unknown. Therefore, we determined in 441 African-born blacks living in America [male: 65% (281/441), age: 38 ± 10 y (mean ± SD), BMI: 27.5 ± 4.4 kg/m<sup>2</sup>] (1) nutritional and hematologic profiles and (2) glucose tolerance categorization by OGTT and A1C.</p><p><bold>Methods:</bold> Hematologic and nutritional status were assessed. Hemoglobin &lt;11 g/dL occurred in 3% (11/441) of patients and led to exclusion. A1C and OGTT were performed in the remaining 430 participants. ADA thresholds for A1C and OGTT were used. Diagnosis by A1C required meeting either A1C-alone or A1C&amp;OGTT criteria. Diagnosis by OGTT-alone required detection by OGTT and not A1C.</p><p><bold>Results:</bold> Hemoglobin, mean corpuscular volume and red blood cell distribution width were 14.0 ± 1.3 g/dL, 85.5 ± 5.3 fL, and 13.2 ± 1.2% respectively. B12, folate, and iron deficiency occurred in 1% (5/430), 0% (0/430), and 4% (12/310), respectively. Heterozygous hemoglobinopathy prevalence was 18% (78/430). Overall, diabetes prevalence was 7% (32/430). A1C detected diabetes in 32% (10/32) but OGTT-alone detected 68% (22/32). Overall prediabetes prevalence was 41% (178/430). A1C detected 57% (102/178) but OGTT-alone identified 43% (76/178). After excluding individuals with heterozygous hemoglobinopathies, the rate of missed diagnosis by A1C of abnormal glucose tolerance did not change (OR: 0.99, 95% CI: 0.61, 1.62).</p><p><bold>Conclusions:</bold> In nutritionally replete Africans without anemia or heterozygous hemoglobinopathy, if only A1C is used, ~60% with diabetes and ~40% with prediabetes would be undiagnosed.</p><p><bold>Clinical Trial Registration:</bold>: <ext-link ext-link-type="uri" xlink:href="http://www.clinicaltrials.gov" xmlns:xlink="http://www.w3.org/1999/xlink">www.ClinicalTrials.gov</ext-link>, Identifier: NCT00001853</p>