Differences in participant classification and intervention effects based on HbA1C and fasting plasma glucose among a community sample of African Americans by Lovoria B Williams in Archives of Diabetes & Obesity in Lupine Publishers
Since 2010, the American Diabetes Association has endorsed both HbA1C (A1C) and fasting plasma glucose (FPG) to determine
diabetes risk. Given the discordance between classifications based on FPG and A1C and higher A1C levels among African Americans
(AAs) than whites, we sought to examine the prevalence of normoglycemia, prediabetes, and diabetes among a community sample
of adult AAs (n=704) screened for enrollment in a randomized Diabetes Prevention Program (DPP). We conducted a retrospective
analysis to estimate the degree of discordance between risk categories based on FPG and A1C and examine the risk factors that
predicted A1C and FPG levels. To determine differential effects on risk categories defined using FPG and A1C, we examined the
effects of the program on the measures at 12 weeks post-intervention among the intervention arm participants.
The tests revealed different prevalence levels at baseline: A1C,
36.2% normoglycemia, 52% prediabetes and 11.8% diabetes;
FPG, 81.1%, 16.8%, and 2%, respectively. There was discordance among A1C
and FPG and among the risk categories (p<0.001).
Both final regression models included age and waist circumference as predictors. For FPG, additional predictors were family history
of diabetes and male gender. Post intervention, only those classified in
the prediabetes category defined in terms of either test
demonstrated intervention effects. Screening test choice results in
different sample composition; both A1C and FPG respond to
intervention effects among individuals classified in the prediabetes group only. These results have implications for research and
clinical practice.
