Classification and Diagnosis

Question 1

Describe the 4 criteria for the diagnosis of diabetes

Answer 1

1. HbA1c >= 6.5% (conducted in NGSP certified lab)
2. FPG >= 126 mg/dL (8 hr fasting)
3. 2 hr PG >= 200 mg/dL during 75 gm OGTT
4. Patient with classic symptoms of hyperglycemia + random CBG >= 200 mg/dL

Question 2

(ADA) Who should be screened for diabetes?

Answer 2

Patients with BMI >= 25 or BMI >= 23 in Asians plus an additional risk factor:

• physical inactivity
• first-degree relative with DM
• high-risk race/ethnicity (African American, Latino, Native American, Pacific Islander)
• Women w/ baby > 9 lbs at birth or GDM
• HTN (>=140/90 or on HTN meds)
• HDL 250 mg/dL
• Women with PCOS
• A1c >= 5.7%, IGT, or IFG on previous testing
• Conditions associated with insulin resistance (severe obesity, acanthosis nigricans)
• Hx CVD

Question 3

All patients, particularly those who are overweight or obese, should be screened for diabetes starting at what age?

Answer 3

45 years old

Even if without risk factors

Question 4

How often should patients with pre diabetes be tested for progression?

Answer 4

Yearly

Question 5

Patients with normal DM screening should have tests repeated at a minimum of every ______

Answer 5

Minimum of every 3 years or more frequently if risk factors change

Question 6

What are the criteria/lab values for pre-diabetes?

Answer 6

Any of the following:

• HbA1c 5.7 - 6.4%
• FPG 100 - 125 mg/dL
• 2-hr PG of 140 - 199 mgdL after 75 gm OGTT

Question 7

When should asymptomatic children be tested for T2DM?

Answer 7

When overweight (BMI > 85th percentile, Wt > 85th percentile, or Wt > 120% IBW) plus 2 risk factors:

• Family hx T2DM in 1st or 2nd degree relative
• High risk race/ethnicity
• Signs of insulin resistance (acanthosis nigricans, HTN, dyslipidemia, PCOS, small-for-gestational-age birth wt)
• Maternal hx of DM or GDM during child’s gestation

Question 8

At what age should DM screening begin for high-risk children?

Answer 8

Age 10 or at onset of puberty, if puberty occurs at a younger age

Question 9

How often should high-risk children be screened for DM?

Answer 9

Every 3 years

Question 10

When should pregnant women be screened for GDM?

Answer 10

• Patients with DM risk factors should be screened at first prenatal visit for undiagnosed T2DM
• All women should be screened at 24 - 28 weeks

Question 11

When and how should postpartum GDM patients be screened for persistent DM?

Answer 11

Screen at 6 - 12 weeks postpartum and use the OGTT

Question 12

If a women with a hx of GDM is found to have pre-diabetes, what are the recommended treatments?

Answer 12

Lifestyle interventions or metformin to prevent progression to DM

Question 13

What is the one-step strategy for screening patients for GDM?

Answer 13

75 gm OGTT after 8 hours of fasting. Diagnosis is made if any glucose value is:

• Fasting >= 92 mg/dL
• 1 hr >= 180 mg/dL
• 2 hr >= 153 mg/dL

Question 14

What is the two-step strategy for screening patients for GDM?

Answer 14

Step 1: 50 gm OGTT (non-fasting) and if 1 hr post glucose >= 140 mg/dL move to step 2 (Note: ACOG recommends >=135 in high risk ethnic groups)
Step 2: 100 gm OGTT (fasting). There are two different cutoffs depending on which guidelines are used. Diagnosis is made if any glucose value is:
- Fasting >= 95 ( or 105 mg/dL)
- 1 hr >= 180 ( or 190 mg/dL)
- 2 hr >= 155 ( or 165 mg/dL)
- 3 hr >= 140 ( or 145 mg/dL)

Question 15

What is MODY?

Answer 15

Maturity-Onset Diabetes of the Young. Rare form of DM that differs from T1DM and T2DM. Caused by gene mutations that are strongly inherited. (High probability if DM present in 3 generations)

Also called monogenic DM

Question 16

What is LADA?

Answer 16

Latent Autoimmune Diabetes of Adults. Sometimes called “Type 1.5 DM” or “double diabetes.” Characterized by latent progression to insulin dependence, presence of autoantibodies, and some insulin resistance.

Question 17

Patients with cystic fibrosis should be screened for DM starting at what age? Via what screening method?

Answer 17

Starting at 10 years old using the OGTT (A1c not recommended).

Question 18

What ethnicities are at higher risk of developing T2DM?

Answer 18

• Native Americans
• African Americans
• Latino
• Asian Americans
• Pacific Islanders

Question 19

(AACE/ACE)

Clinicians may consider screening patients yearly for DM if they have 2 or more risk factors. What are the risk factors?

Answer 19

• CVD
• Family hx T2DM
• Overweight or obese
• At risk ethnic group
• HDL 250 mg/dL
• IGT, IFG, and/or metabolic syndrome
• PCOS, acanthosis nigricans, NAFLD
• HTN (140/90 or on tx for HTN)
• Hx GDM or delivering baby more than 9 lbs
• Antipsychotic therapy for schizophrenia and/or severe bipolar dz
• Chronic glucocorticoid exposure
• Sleep disorders in the presence of glucose intolerance (pre-DM + OSA, chronic sleep deprivation, night-shift occupation)

Question 20

What tests require repeat testing for confirmation of DM diagnosis and which do not?

Answer 20

All tests should be confirmed a different day using the same test (HBA1c or plasma glucose) except when glucose >= 200 me/dL and having classic sx

Question 21

What condition is considered a pre diabetes equivalent?

Answer 21

Metabolic Syndrome (as defined by NCEP ATP III criteria)

Question 22

T1DM is characterized by absolute insulin deficiency. How should the dx be confirmed?

Answer 22

1. Insulin levels
2. C-peptide levels
3. Check for autoantibodies to:
   - glutamic acid decarboxylase
   - pancreatic islet beta cells (tyrosine phosphatase IA-2)
   - Zinc transporter
   - Insulin
   - If no autoantibodies = idiopathic T1DM