Use of HbA1c in the diagnosis of diabetes in adolescents

Objective. To examine the screening practices of family practitioners (FPs) and pediatricians for type 2 diabetes (T2D) in adolescents. Design. Cross-sectional study. Setting and participants. The researchers randomly sampled 700 pediatricians and 700 FPs who participated in direct patient care using the American Medical Association Physician Masterfile using a mail survey. Exclusion criteria included providers who were residents, hospital staff, retirees, or employed by federally owned medical facilities, certified with a subspecialty, or over age 70. Main outcome measures. Providers were given a hypothetical case of an obese, female, teenaged patient with concurrent associated risk factors for T2D (family history of T2D, minority race, signs of insulin resistance) and asked what initial screening tests they would order. Respondents were then informed of the updated American Diabetes Association (ADA) guidelines that added hemoglobin A1c as a screening test to diagnose diabetes. The survey then asked if knowing this change in recommendation has changed or will change their screening practices in adolescents. Main results. 1400 surveys were mailed. After 2 were excluded due to mailing issues, 52% of providers provided responses. Of these, 129 providers reported that they did not care for adolescents (age 10-17), resulting in 604 providers in the final sample, 398 pediatricians and 335 FPs. The vast majority (92%) said they would screen the hypothetical case for diabetes, with most initially ordering a fasting test (fasting plasma glucose or 2-hour glucose tolerance test) (63%) or A1c test (58%). Of the 58% who planned to order HbA1c, only 35% ordered it in combination with a fasting test. HbA1c was significantly more likely to be ordered by pediatricians than by FPs (P = 0.001). After being presented with the new guidelines, 84% said then would now order HbA1c, a 27% increase. Conclusion. In response to information about the new guidelines, providers were more likely to order A1c as part of initial testing. Due to the lower test performance in children and increased cost of the test, the use of HbA1c without fasting tests may result in missed diagnosis of T2D in adolescents as well as increased health care costs.