Spuriously high prevalence of prediabetes diagnosed by HbA(1c) in young indians partly explained by hematological factors and iron deficiency anemia.
OBJECTIVE
To examine the influence of glycemic and nonglycemic parameters on HbA(1c) concentrations in young adults, the majority of whom had normal glucose tolerance.


METHODS
We compared the diagnosis of normal glucose tolerance, prediabetes, and diabetes between a standard oral glucose tolerance test (OGTT; World Health Organization 2006 criteria) and HbA(1c) concentrations (American Diabetes Association [ADA] 2009 criteria) in 116 young adults (average age 21.6 years) from the Pune Children's Study. We also studied the contribution of glycemic and nonglycemic determinants to HbA(1c) concentrations.


RESULTS
The OGTT showed that 7.8% of participants were prediabetic and 2.6% were diabetic. By ADA HbA(1c) criteria, 23.3% were prediabetic and 2.6% were diabetic. The negative predictive value of HbA(1c) was 93% and the positive predictive value was 20% (only 20% had prediabetes or diabetes according to the OGTT; this figure was 7% in anemic participants). Of participants, 34% were anemic, 37% were iron deficient (ferritin <15 ng/mL), 40% were vitamin B(12) deficient (<150 pmol/L), and 22% were folate deficient (<7 nmol/L). On multiple linear regression analysis, HbA(1c) was predicted by higher 2-h glucose (R(2) = 25.6%) and lower hemoglobin (R(2) = 7.7%). When hematological parameters were replaced by ferritin, vitamin B(12), and folate, HbA(1c) was predicted by higher glycemia (R(2) = 25.6%) and lower ferritin (R(2) = 4.3%).


CONCLUSIONS
The use of HbA(1c) to diagnose prediabetes and diabetes in iron-deficient populations may lead to a spuriously exaggerated prevalence. Further investigation is required before using HbA(1c) as a screening tool in nutritionally compromised populations.
Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India.
Pallavi S
PS
Hardikar
Suyog M
SM
Joshi
Dattatray S
DS
Bhat
Deepa A
DA
Raut
Prachi A
PA
Katre
Himangi G
HG
Lubree
Abhay
A
Jere
Anand N
AN
Pandit
Caroline H D
CH
Fall
Chittaranjan S
CS
Yajnik
D000328:Adult; D018798:Anemia, Iron-Deficiency / Q000097:blood* / Q000150:complications / Q000453:epidemiology; D044466:Asian People / Q000706:statistics & numerical data; D015982:Bias; D001786:Blood Glucose / Q000032:analysis; D015331:Cohort Studies; D015340:Epidemiologic Research Design; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis*; D006402:Hematologic Diseases / Q000097:blood* / Q000150:complications / Q000453:epidemiology; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D011236:Prediabetic State / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D015995:Prevalence; D012107:Research Design; D055815:Young Adult
D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human