Prediabetes is on the rise and thus likely to appear in your USMLE, ABIM, and PANCE questions
A new UCLA study released last week found that 46% of adults in California are pre-diabetic, leading many media outlets to report on this diagnosis. Combining the 9% who have diabetes, the researchers found that over 1/2 of Californians have either diabetes or pre-diabetes. National numbers are also alarming, with the Centers for Disease Control and Prevention estimating that 86 million adults are prediabetic, making it an important public health issue. Given the increasing emphasis on preventative medicine, prediabetes is a topic that is often tested on various medical board examinations.
Here’s what you need to know about prediabetes for the Medical Shelf, USMLE, In-Training Exam (ITE), ABIM and PANCE/PANRE.
How do you define pre-diabetes?
The Los Angeles Times described pre-diabetes to the lay public as “blood glucose levels are higher than normal but not high enough to be considered diabetic.” That is, of course, very much accurate. Additionally, though, for the purposes of our exams, we need to know the specific diagnostic criteria.
What is the fasting blood sugar criteria for prediabetes?
Prediabetes is defined as two or more fasting blood sugar values of 100-125mg/dL.
What is the two hour post-glucose load criteria for prediabetes?
Prediabetes is defined as blood sugar of 140-199mg/dL two hours after a 75g glucose load.
What is the hemoglobin A1c criteria for prediabetes?
Prediabetes is defined as hemoglobin A1c between 5.7% and 6.4%.
What is the random blood sugar criteria for prediabetes?
There is no random blood sugar criteria for prediabetes.
What about diabetes?
Diabetes can be diagnosed in patients who have:
- Two fasting blood glucose greater than or equal to 126mg/dL OR
- Blood sugar greater than or equal to 200mg/dL 2 hours after a 75g load of oral glucose OR
- A random blood glucose greater than or equal to 200mg/dL in the context of polyuria, polydipsia, or unintentional weight loss
The visual below summarizes the key diagnostic criteria for prediabetes and diabetes, as relevant for the Medical Shelf, USMLE, In-Training Exam (ITE), ABIM and PANCE/PANRE.
What should we recommend to our patients with pre-diabetes?
Those patients who are overweight must first focus on diet and exercise. In fact, a frequently-quoted 2008 study found that people with pre-diabetes who were overweight and improved their diet and exercise reduced their diabetes risk by 58%. Those who instead took metformin (a biguanide) at a dose of 850mg twice daily reduced their risk only 31%. So, as is usually the case on these medical exams, choose lifestyle modification before prescribing a pill.