2010 ADA Guidelines: 1. Diagnostic Criteria for DM 2. Categories of increased risk of DM. Gerti Tashko, M.D. DM Journal Club 1/21/2010

Transcription

1 2010 ADA Guidelines: 1. Diagnostic Criteria for DM 2. Categories of increased risk of DM Gerti Tashko, M.D. DM Journal Club 1/21/2010

2 NEW: Diagnosis with A1c 6.5% Cut point of A1c 6.5% diagnoses 33% less cases than Fasting Glucose 126 mg/dl. If two tests are discordant, repeat the one that is abnormal. 1. If the test is again abnormal, then patient has diabetes. 2. If the test is normal, then repeat testing in 3-6 months. High risk for diabetes if A1c = % Patients with A1c = 6-6.5% are considered to be at very high risk for developing diabetes: 10 x more likely than those with A1c < 6.0% patients with A1c % are considered to be at high risk for diabetes Start Metformin in patients with combined IFG, IGT + A1c > 6%

3 NEW: Glucose Goals for treatment: For all patients: A1c < 7% (old, for reference point) A1c could be tighter (like < 6.5%) in those with: 1. Short duration of diabetes. 2. Long life expectancy. 3. No significant cardiovascular disease. A1c could be higher (like 8%) in those with: 1. History of severe hypoglycemia 2. Limited life expectancy. 3. Advanced micro- and macro complications. 4. long-standing diabetes.

4 Diagnostic Criteria for DM A1c 6.5% (new) or FPG 126 mg/dl fasting for 8 hours or 75 gr, 2hr OGTT 200 mg/dl or Random Glucose 200 mg/dl + symptoms of hyperglycemia Repeat testing if uncertain.

5 Important information: In 1997 diagnostic criteria for DM based on IFG and IGT were revised, so that IFG and IGT cutoff points reflected early stages of retinopathy. A1c is included as diagnostic criteria this time, because it is felt that A1c assays are now highly standardized and can be uniformly applied. A1c 6.5% is chosen because of its relation with early stages of retinopathy (just like with IFG and IGT) Point-of-care A1c should not be used at this time for diagnostic purposes.

6 Pluses & Minues of using A1c: Pluses: 1. Convenience, since requires non-fasting state. 2. Has no day-to-day fluctuations. Minuses: 1. Costs more 2. limited availability in certain coutries. 3. Could be misleading in patients with anemia and hemoglobinopathies. Those with abnormal red cell turnover (hemolysis, iron deficiency anemia) it is recommended to use glucose criteria, and not the A1c.

7 A1c is less sensitive: 1. Cut point of A1c 6.5% diagnoses 33% less cases than Fasting Glucose 126 mg/dl. 2. However, due to its greater convenience, practicality and wider application overall A1c criteria may actually increase the number of patients diagnosed with diabetes.

8 What if there is discordance with A1c? No test is preferred over others for diagnosing diabetes. The decision should be made on the physician s preference, and availability, practicality, and cost of the test. A1c = least variable Fasting Glucose = more variable 2hr OGTT = most variable. If two tests are discordant, repeat the one that is abnormal. 1. If the test is again abnormal, then patient has diabetes. 2. If the test is normal, then repeat testing in 3-6 months.

9 Categories of increased risk for DM: A1c = % (new) Fasting Glucose = mg/dl 2hr OGTT = mg/dl Important to note that all 3 tests represent a continuous risk of developing diabetes that extends even below the lower limits.

10 More on A1c criteria: Patients with A1c = 6-6.5% are considered to be at very high risk for developing diabetes: 10 x more likely than those with A1c < 6.0% However, a good portion of patients with A1c range 6-6.5% do NOT have impaired fasting glucose, or impaired glucose tolerance emphasizing the fact that A1c is less sensitive but more specific test.

11 NHANES (survey) data indicate that A1c range between % corresponds best with IFG and IGT. Therefore, arbitrarily 5.7% midpoint was chosen as the cut off value for identifying those at risk for diabetes. As with diagnostic criteria, A1c (5.7%) is less sensitive but more specific than fasting glucose criteria. Sensitivity ~ 45% Specificity~ 85% Therefore, patients with A1c % could be considered to be at high risk for diabetes

12 When should we screen for diabetes: 1. All patients 45 years of age. 2. All patients with BMI 25 kg/m 2 + any of the following: 1. Hypertension of 140/90 mmhg 2. HDL < 35 mg/dl, or Triglycerides > 250 mg/dl 3. Clinical insulin resistance (severe visceral obesity, acanthosis nigricans) 4. History of cardiovascular disease. 5. gestational DM, or delivered a baby > 9 lbs 6. African/Lationo/Native/Asian American or Pacific islander 7. First degree relative with diabetes 8. physically inactive 3. If testing is normal, then repeat screening in 3 years.

13 How to prevent Diabetes: If patient has A1c %, or IFG, or IGT then it is recommended: 5-10% weight loss in ~6 months. 150 min of moderate exercise, like walking. Start Metformin in the very high risk patients: Combined IFG + IGT and the following: A1c > 6% HTN Low HDL, high TGs Family history Obese and <60 years of age.

14 What is the glucose target for treatment? For all patients: A1c < 7% A1c could be tighter (like < 6.5%) in those with: 1. Short duration of diabetes. 2. Long life expectancy. 3. No significant cardiovascular disease. A1c could be higher (like 8%) in those with: 1. History of severe hypoglycemia 2. Limited life expectancy. 3. Advanced micro- and macro complications. 4. long-standing diabetes.