Prediabetes is a health condition where the blood sugar levels are higher than normal, but not high enough yet to be diagnosed as type 2 diabetes. It is an intermediate stage between normal glucose regulation and diabetes, affects 1 in 3 adults in the US and approximately 720 million individuals worldwide.
There are no clear symptoms of prediabetes so you may have it and not know it. But before people develop type 2 diabetes, they almost always have prediabetes—where blood glucose levels are higher than normal but not yet high enough to be diagnosed as diabetes. It is possible that you may have some of the symptoms of diabetes or even some of the complications.
Diagnosis of Prediabetes
Slightly different diagnostic criteria for prediabetes have been proposed by the American Diabetes Association (ADA), World Health Organization (WHO), and the International Expert Committee.
These criteria include impaired fasting glucose, which is based on a fasting glucose level, and impaired glucose tolerance, which is based on a 2hPG. The American Diabetes Association impaired fasting glucose criterion is specified by fasting glucose level of 100 to 125 mg/dL (5.5-6.9 mmol/L). The impaired glucose tolerance criterion is met by a 2hPG of 140 to 199 mg/dL (7.8-11.0 mmol/L).
Prediabetes is also defined with an HbA1c level of 5.7% to 6.4% by the American Diabetes Association or an HbA1c level of 6.0% to 6.4% by the International Expert Committee. As a test for the initial diagnosis of diabetes or prediabetes, HbA1c has the advantage of convenience (no fasting required) compared with fasting plasma glucose level or 2hPG. However, HbA1c may be unreliable as a measure of time-averaged blood glucose levels under certain conditions (eg, hemolytic anemia, iron deficiency, hemoglobinopathies, pregnancy, uremia).
As per American Diabetes Association (ADA), criteria defining prediabetes are mentioned below:
| FPG 100 mg/dL (5.6 mmol/L) to 125 mg/dL (6.9 mmol/L) (IFG) |
| OR |
| 2-h PG during 75-g OGTT 140 mg/dL (7.8 mmol/L) to 199 mg/dL (11.0 mmol/L) (IGT) |
| OR |
| A1C 5.7–6.4% (39–47 mmol/mol) |
Diagnostic Tests for Diabetes or Prediabetes
As per ADA, criteria for testing for diabetes or prediabetes in asymptomatic adults are mentioned below:
| 1. Testing should be considered in adults with overweight or obesity (BMI ≥25 kg/m2 or ≥23 kg/m2 in Asian Americans) who have one or more of the following risk factors: |
| - First-degree relative with diabetes |
| - High-risk race/ethnicity (e.g., African American, Latino, Native American, Asian American, Pacific Islander) |
| - History of CVD |
| - Hypertension (≥140/90 mmHg or on therapy for hypertension) |
| - HDL cholesterol level <35 mg/dL (0.90 mmol/L) and/or a triglyceride level >250 mg/dL (2.82 mmol/L) |
| - Women with polycystic ovary syndrome |
| - Physical inactivity |
| - Other clinical conditions associated with insulin resistance (e.g., severe obesity, acanthosis nigricans) |
| 2. Patients with prediabetes (A1C ≥5.7% [39 mmol/mol], IGT, or IFG) should be tested yearly. |
| 3. Women who were diagnosed with GDM should have lifelong testing at least every 3 years. |
| 4. For all other patients, testing should begin at age 45 years. |
| 5. If results are normal, testing should be repeated at a minimum of 3-year intervals, with consideration of more frequent testing depending on initial results and risk status. |
| 6. HIV |
CVD = cardiovascular disease; GDM = gestational diabetes mellitus; IFG = impaired fasting glucose; IGT = impaired glucose tolerance.
Management of Prediabetes
a) Lifestyle Modifications
- Decrease caloric intake by 700 kcal/d, targeting saturated fats and simple sugars.
- Increase activity to ≥30 min/day on 5 or more days per week.
- Goals are individualized, typically ≥7% of body weight if overweight or having obesity.
- Smoking cessation, improved sleep hygiene, and stress reduction.
- Frequent in-person visits initially, followed by less frequent visits with optional virtual visits to therapy team.
b) If suboptimal response to lifestyle intervention occur, metformin therapy is subjected for the patient and should assess patients for vitamin B12 deficiency during prolonged metformin therapy.
References:
- JAMA, Volume 329, Number 14
- ADA guidance on Diagnosis and Prevention of Prediabetes