Racial Differences in the Relationship of Glucose Concentrations and Hemoglobin A<sub>1c</sub> Levels

Bergenstal, Richard M.; Gal, Robin L.; Connor, Crystal G.; Gubitosi-Klug, Rose; Kruger, Davida F.; Olson, Beth A.; Willi, Steven M.; Aleppo, Grazia; Weinstock, Ruth S.; Wood, Jamie; Rickels, Michael R.; DiMeglio, Linda A.; Bethin, Kathleen E.; Marcovina, Santica; Tassopoulos, Andreana; Lee, Sooji; Massaro, Elaine; Bzdick, Suzan; Ichihara, Brian; Markmann, Eileen; McGuigan, Paul; Woerner, Stéphanie; Ecker, Michelle; Beck, Roy W.

doi:10.7326/m16-2596

Cited by 249 publications

(191 citation statements)

References 39 publications

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“…For example, African Americans may have higher A1C levels than nonHispanic whites with similar fasting and postglucose load glucose levels (16), and A1C levels may be higher for a given mean glucose concentration when measured with continuous glucose monitoring (17). Though conflicting data exists, African Americans may also have higher levels of fructosamine and glycated albumin and lower levels of 1,5-anhydroglucitol, suggesting that their glycemic burden (particularly postprandially) may be higher (18,19).…”

Section: Race/ethnicity/hemoglobinopathiesmentioning

confidence: 99%

2. Classification and Diagnosis of Diabetes:Standards of Medical Care in Diabetes—2018

2017

Diabetes Care

2,556

1,223

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The American Diabetes Association (ADA) “Standards of Medical Care in Diabetes” includes ADA’s current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA’s clinical practice recommendations, please refer to the Standards of Care Introduction. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

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Section: Race/ethnicity/hemoglobinopathiesmentioning

confidence: 99%

2. Classification and Diagnosis of Diabetes:Standards of Medical Care in Diabetes—2018

2017

Diabetes Care

2,556

1,223

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“…A meta-analysis of non-diabetic participants demonstrated statistically significantly higher levels of HbA1c in black (2.8 mmol/mol, 95% CI 0.18 to 0.33), Asian (2.6 mmol/mol, 95% CI 0.16 to 0.33) and Latino cohorts (0.9 mmol/mol, 95% CI 0.06 to 0.10) compared with Caucasian 45. In a prospective study using continuous glucose monitoring and comparing 104 black and 104 white patients with known T1DM over 12 weeks, black patients had on average an HbA1c higher by 0.4% than whites for comparable average glucose measures 46. While these differences are not of definitive clinical significance, the results do suggest further work should be undertaken to better understand the impact of ethnicity on HbA1c.…”

Section: Non-glycaemic Biological Variablesmentioning

confidence: 99%

HbA1c: a review of non-glycaemic variables

Campbell

Pepper

Shipman³

2018

J Clin Pathol

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Identification of the correlation between HbA1c and diabetic complications has yielded one of the most clinically useful biomarkers. HbA1c has revolutionised the diagnosis and monitoring of diabetes mellitus. However, with widespread adoption of HbA1c has come increasing recognition that non-glycaemic variables can also affect HbA1c, with varying clinical significance. Furthermore, the identification of a discrepancy between predicted and measured HbA1c in some individuals, the so-called ‘glycation gap’, may be clinically significant. We aimed to review the current body of evidence relating to non-glycaemic variables to quantify any significance and provide subsequent suggestions. A PubMed-based literature search was performed, using a variety of search terms, to retrieve articles detailing the non-glycaemic variables suggested to affect HbA1c. Articles were reviewed to assess the relevance of any findings in clinical practice and where possible guidance is given. A range of non-glycaemic variables have statistically significant effects on HbA1c. While the clinical implications are generally irrelevant, a small number of non-glycaemic variables do have clinically significant effects and alternative biomarkers should be considered instead of, or in addition to, HbA1c. There are a small number of non-glycaemic variables which have a clinically significant effect on HbA1c, However, the vast majority of non-glycaemic variables have no clinical relevance. While clinicians should have an awareness of those non-glycaemic variables with clinical significance, in the vast majority of clinical scenarios HbA1c should continue to be used with confidence.

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“…This distinction in utilizing HbA 1c to compare groups versus its use in determining glycemic control for an individual was illustrated in a recent study we and others conducted assessing racial differences in the mean glucose–HbA 1c relationship (4). The study showed that on average HbA 1c levels in blacks are about 0.4% (4.4 mmol/mol) higher than those of whites for a given mean glucose concentration determined with continuous glucose monitoring (CGM).…”

Section: Introductionmentioning

confidence: 99%

“…The analysis was conducted on a data set with a median of 13 days of CGM measurements plus 39 days of fingerstick blood glucose measurements. To assess the mean glucose–HbA 1c relationship with current CGM technology and a greater amount of data, we pooled data collected in 387 participants (age range 20–78 years, 83% white, 315 with type 1 diabetes and 72 with type 2 diabetes) in three randomized trials using the Dexcom G4 Platinum CGM System with an enhanced algorithm, software 505 (Dexcom, Inc., San Diego, CA) (4,15,16). Mean glucose concentration was determined for each participant using up to 13 weeks of CGM data (median amount of CGM data 66 days) and plotted versus HbA 1c measured following the collection of the CGM data at the Northwest Lipid Research Laboratories, University of Washington, Seattle, WA, using nonporous ion exchange high-performance chromatography (TOSOH, Biosciences, Inc., South San Francisco, CA).…”

Section: Introductionmentioning

confidence: 99%

The Fallacy of Average: How Using HbA1c Alone to Assess Glycemic Control Can Be Misleading

et al. 2017

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HbA1c is a valuable metric for comparing treatment groups in a randomized trial, for assessing glycemic trends in a population over time, or for cross-sectional comparisons of glycemic control in different populations. However, what is not widely appreciated is that HbA1c may not be a good indicator of an individual patient’s glycemic control because of the wide range of mean glucose concentrations and glucose profiles that can be associated with a given HbA1c level. To illustrate this point, we plotted mean glucose measured with continuous glucose monitoring (CGM) versus central laboratory–measured HbA1c in 387 participants in three randomized trials, showing that not infrequently HbA1c may underestimate or overestimate mean glucose, sometimes substantially. Thus, if HbA1c is to be used to assess glycemic control, it is imperative to know the patient’s actual mean glucose to understand how well HbA1c is an indicator of the patient’s glycemic control. With knowledge of the mean glucose, an estimated HbA1c (eA1C) can be calculated with the formula provided in this article to compare with the measured HbA1c. Estimating glycemic control from HbA1c alone is in essence applying a population average to an individual, which can be misleading. Thus, a patient’s CGM glucose profile has considerable value for optimizing his or her diabetes management. In this era of personalized, precision medicine, there are few better examples with respect to the fallacy of applying a population average to a specific patient rather than using specific information about the patient to determine the optimal approach to treatment.

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Racial Differences in the Relationship of Glucose Concentrations and Hemoglobin A_1c Levels

Abstract: Helmsley Charitable Trust.

Cited by 249 publications

References 39 publications

2. Classification and Diagnosis of Diabetes:Standards of Medical Care in Diabetes—2018

2. Classification and Diagnosis of Diabetes:Standards of Medical Care in Diabetes—2018

HbA1c: a review of non-glycaemic variables

The Fallacy of Average: How Using HbA1c Alone to Assess Glycemic Control Can Be Misleading

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Racial Differences in the Relationship of Glucose Concentrations and Hemoglobin A1c Levels

Abstract: Helmsley Charitable Trust.

Cited by 249 publications

References 39 publications

2. Classification and Diagnosis of Diabetes:Standards of Medical Care in Diabetes—2018

2. Classification and Diagnosis of Diabetes:Standards of Medical Care in Diabetes—2018

HbA1c: a review of non-glycaemic variables

The Fallacy of Average: How Using HbA1c Alone to Assess Glycemic Control Can Be Misleading

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Product

Resources

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Racial Differences in the Relationship of Glucose Concentrations and Hemoglobin A_1c Levels