Screening for Prediabetes and Type 2 Diabetes

The US Preventive Services Task Force (USPSTF) has recently published recommendations on screening for prediabetes and type 2 diabetes.

Prediabetes and diabetes are conditions in which glucose (sugar) is not metabolized normally, resulting in high blood sugar levels. The cause of this abnormal sugar metabolism is a problem with insulin, a hormone produced by the pancreas that helps regulate sugar level. In type 2 diabetes, the body stops responding properly to insulin (insulin resistance), and eventually the pancreas stops making enough insulin.

Prediabetes means a person has a blood sugar level that is higher than normal but not yet in the range of what is considered diabetes. Prediabetes increases the risk of developing diabetes, but it does not always progress to diabetes. Exercise, a healthy diet, and weight loss if you are overweight or obese are all effective ways to prevent diabetes. Risk factors for developing prediabetes and diabetes include being overweight or obese, older age, and having family members with diabetes.

Symptoms of diabetes result from a high blood sugar level and include being very thirsty and urinating more often. Over time, diabetes can lead to cardiovascular disease, kidney disease, and blindness. Besides lifestyle changes, diabetes can be treated with a variety of medications, including pills and injections (which include both insulin and noninsulin injections).

Screening for prediabetes and diabetes is done by checking blood sugar level. There are several tests that can be used to assess blood sugar, including fasting glucose measurement, hemoglobin A_1c measurement, and an oral glucose tolerance test.

This recommendation applies to nonpregnant adults aged 35 to 70 years who are overweight or obese and have no symptoms of diabetes.

The goal of screening for prediabetes and diabetes is to identify and treat these conditions earlier rather than later to prevent progression of disease and adverse outcomes such as heart attack, kidney disease, impaired vision, and death. While there is limited direct evidence that screening for prediabetes and diabetes improves health outcomes, there is good direct evidence that interventions for newly diagnosed diabetes have a moderate benefit in reducing all-cause mortality, diabetes-related mortality, and risk of heart attack after 10 to 20 years of intervention. Furthermore, there is convincing evidence that lifestyle interventions such as diet and exercise in those who have prediabetes reduce progression to type 2 diabetes.

Potential harms of screening are small. These may include psychological stress from a diagnosis of prediabetes or diabetes, as well as potential side effects of treatment, such as low blood sugar level (hypoglycemia) or gastrointestinal side effects from metformin.

The USPSTF concludes with moderate certainty that screening for prediabetes and type 2 diabetes in adults who are overweight or obese and offering or referring patients with prediabetes to effective preventive interventions has a moderate net benefit.

Conflict of Interest Disclosures: None reported.

Source: US Preventive Services Task Force. Screening for prediabetes and type 2 diabetes: US Preventive Services Task Force recommendation statement. JAMA. Published August 24, 2021. doi:10.1001/jama.2021.12531