Diabetes: Rethinking risk and the Dx that fits

The youngest Americans—those born in the year 2000 or thereafter—have more than a 1 in 3 lifetime risk of developing diabetes, according to the Centers for Disease Control and Prevention.¹ That estimate, coupled with the fact that more than 2 out of 3 adults and 1 in 6 children between the ages of 2 and 19 years are overweight,² would seem to indicate a need for widespread diabetes screening. But limited health care resources, a lack of evidence that mass screening improves outcomes, and differences among leading medical associations about whom and when to screen argue against it.

At the same time, widespread obesity is making the presentation of hyperglycemia more complex and the forms of diabetes harder to classify. Many cases don’t follow the classic patterns, in which type 1 (formerly called juvenile diabetes) virtually always emerges in childhood and type 2 (previously known as adult-onset diabetes) is strictly an adult disease. Our evolving understanding of diabetes has led researchers to focus on prediabetes (defined as impaired fasting glucose, impaired glucose tolerance, or both) and latent autoimmune diabetes in adults (LADA), a recently reported type 1 variant that some have labeled type 1.5.³

In the face of growing complexity, the US Preventive Services Task Force (USPSTF) last year upgraded its recommendation for screening for type 2 diabetes, and researchers have developed new risk calculation tools. We’ve taken a look at the changing clinical landscape and sorted through the latest evidence to help you make sense of the latest risk and diagnostic developments in diabetes care.

Screening for type 2: A look at guidelines

Type 2 diabetes accounts for approximately 90% of the cases you’ll see.^1,4,5 The American Diabetes Association (ADA) calls for routine screening, starting at 45 years of age and continuing every 3 years thereafter in the absence of risk. But for those who are overweight or obese and have 1 or more additional risk factors, screening is recommended at any age.⁵ In addition to a body mass index (BMI) ≥25, risks include physical inactivity, a first-degree relative with type 2 diabetes, blood pressure >135/80 mm Hg (or controlled with an antihypertensive), high-density lipoproteins (HDL) <35 mg/dL, triglycerides >250 mg/dL, polycystic ovary syndrome, impaired glucose tolerance or impaired fasting glucose, and acanthosis nigricans, a pigmented thickening of the skin folds of the neck (TABLE).^6,7 Patients with the metabolic syndrome—abdominal obesity (defined as a waist circumference of >40” in men and >35” in women) and ≥2 of the following: raised triglyceride levels, elevated blood pressure, elevated fasting plasma glucose, and reduced HDL cholesterol—are at especially high risk of both cardiovascular disease and type 2 diabetes.⁸

The ADA screening recommendations, however, are not based on prospective outcome studies, nor are they widely followed. Until recently, the USPSTF only recommended screening adults with hypertension and hyperlipidemia.

In 2008, after an assessment of new findings and research updates, the USPSTF revised its recommendation: The task force now calls for screening asymptomatic adults with sustained blood pressure >135/80 mm Hg—regardless of lipid profile.⁷ For patients with diabetes and hypertension, the USPSTF concluded, evidence shows that early intervention—including lowering blood pressure below conventional targets—can prevent long-term adverse outcomes of diabetes and reduce the risk of cardiovascular events.