Question

• In at-risk adolescent patients what is the utility of a random HbA1c level in the diagnosis of type 2 diabetes mellitus?

Clinical Bottom Lines

1. HbA1c levels above 6.1% is a useful predictor of type 2 diabetes mellitus.
   
2. Testing glucose tolerance with HbA1c levels is convenient and may lead to earlier identification of type 2 diabetes mellitus in selected populations.

Summary of Key Evidence

1. Prevalence of type 2 diabetes mellitus in children is rising, current recommendations are to screen children >10 with obesity, family hx, acanthoisis nigricans, or genetically susceptible background.
   
2. HbA1c testing correlates with long term glucose control and is a standardized laboratory test.
   
3. HbA1c level shows minimal variability with time of the day and fasting vs non-fasting state.

Additional Comments

• Elevated HbA1c is not a current criteria for the diagnosis of diabetes.
  
• HA1c testing is three times as expensive as fasting glucose level.
  
• The early diagnosis of type 2 diabetes in children has an unknown effect of disease outcome.
  

Citation

1. American Diabetes Association: Type 2 diabetes in children and adolescents. American Academy of Pediatrics 2000; 105(3): 671-680.
   
2. Aye T, Levitsky LL. Type 2 diabetes: an epidemic disease in childhood. Current opinion in Pediatrics 2003; 15(4): 411-415.
   
3. Caragher TE, Dohna JC, Lomont ME. Cautionary note regarding HbA1c methods predicting the clinical status of diabetic patients. Diabetes Care 2000; 23(6): 867-869.
   
4. Rohlfing CL, Little RR, et. al. Use of GHb (HbA1c) in screening for undiagnosed diabetes in the U.S. population. Diabetes Care 2000; 23(2): 187-191.

CAT Author: Brendan Kelly, MD

CAT Appraisers: Kenneth Pituch, MD

Date appraised: March 24, 2004