SCREENING AND PREVENTION

Screening for Diabetes

Testing to detect type 2 diabetes and assess risk for future diabetes in patients who are asymptomatic should be conducted for patients who are overweight or obese or who have one or more additional risk factors for diabetes, such as:

• Physical inactivity
• First-degree relative with diabetes
• High-risk race/ethnicity (e.g., African American, Latino, Native American, Asian American, Pacific Islander)
• Woman who delivered a baby weighing 9 pounds or more or was diagnosed with gestational diabetes (diabetes diagnosed during pregnancy that is not clearly overt diabetes)
• Hypertension (140/90 mmHg or higher or receiving treatment for hypertension)
• HDL cholesterol level of 35 mg/dL or lower and/or a triglyceride level of 250 mg/dL or higher
• Woman with polycystic ovarian syndrome
• A1C of 5.7% or higher, impaired glucose tolerance (IGT), or impaired fasting glucose (IFG) on previous testing (see “Laboratory Tests” later in this course)
• Other clinical conditions associated with insulin resistance (e.g., severe obesity, acanthosis nigricans [skin condition characterized by areas of dark, velvety discoloration in body folds and creases], metabolic syndrome)
• History of cardiovascular disease
  (ADA, 2020b; Merck Manual 2019b)

In the absence of the above risk factors, testing for diabetes should begin at age 45 years. If results are normal, testing should be repeated at least at three-year intervals; more frequent testing should be considered depending on initial results and risk status (ADA, 2020b).

Prevention and Prediabetes

People whose bodies do not handle blood sugar optimally have a condition called prediabetes, which places them at high risk of developing type 2 diabetes (ADA, 2020b). Most people with prediabetes are unaware they have it.

SCREENING FOR PREDIABETES

The ADA recommends screening for prediabetes for all adults aged 45 and older. Testing should also be completed every three years starting at age 29 for those who are overweight (defined as a BMI >25 kg/m²) and have additional risk factors, including:

• Cardiovascular disease
• Hypertension
• High triglycerides or low HDL
• Sedentary lifestyle
• Non-White race
• Family history (first-degree relative) of diabetes
  (ADA, 2020b)

Prediabetes can be recognized through the same screening tests used to diagnose diabetes. The simplest test is the fasting plasma glucose (FPG) level. In prediabetes, FPG is in the impaired range (100–125 mg/dL) in measurements taken on two different days. Alternately, an oral glucose tolerance test (OGTT) in the impaired range (140–199 mg/dL at 2 hours), again on two different days, can be used to diagnose prediabetes (ADA, 2020b).

In addition to signaling a person’s risk for developing type 2 diabetes, prediabetes warns that the person also has a higher risk for heart disease and stroke.

TREATING PREDIABETES

A program of weight loss and increased physical activity can improve the problems underlying prediabetes, and many times, lifestyle changes alone can prevent people with prediabetes from going on to develop diabetes.

Recently, a task force of experts issued a set of guidelines for people diagnosed with prediabetes. The new guidelines prompted the ADA to recommend the same cardiovascular treatment goals for prediabetes as for diabetes. These goals include:

• HDL cholesterol levels >50 mg/dL for women and >40 mg/dL for men
• Triglyceride levels <150 mg/dL
• Blood pressure measured at every routine visit with healthcare providers
• Blood pressure <140/90 mmHg. Lower systolic and diastolic blood pressure targets, such as 130/80 may be appropriate for persons at high risk of cardiovascular disease if these targets can be achieved without undue treatment burden.
  (ADA, 2020c)

In terms of what needs to be done if a person is diagnosed with prediabetes, the first step is to initiate lifestyle changes, including exercising and eating a healthy diet (e.g., fruits, nonstarchy vegetables, lean meats, nonfat dairy products). Weight loss goals for people with prediabetes include losing 7% of their body weight and doing moderate-intensity physical activity (such as brisk walking) at least 150 minutes/week (ADA, 2020d).

Additionally, people with prediabetes should not smoke and should avoid excessive alcohol consumption (i.e., no more than one drink a day for women and two drinks for men).

Antidiabetes drug therapy may be considered for high-risk patients with prediabetes who are unable to control their blood sugar with weight loss and exercise. Research shows that drugs such as metformin (Glucophage) or acarbose (Precose) can delay the onset of type 2 diabetes in people with prediabetes, but not nearly as effectively as lifestyle changes (ADA, 2020d).