The U.S. Preventive Services Task Force (USPSTF) has added a B-level recommendation for abnormal blood glucose screening in overweight or obese adults aged 40-70 years as a part of their cardiovascular risk assessment. The guidelines were published in the Annals of Internal Medicine on Oct 26.
“Losing weight reduces the chances of developing diabetes, which is why our recommendation focuses on diet and exercise. Patients who have abnormal blood sugar levels can be referred to programs that help them eat a more healthful diet and exercise more often,” noted task force member Dr. William Phillips of the departments of health services and epidemiology at the University of Washington, Seattle, in a statement.
An estimated one-quarter of the cardiovascular disease (CVD) deaths are considered preventable. Likewise, abnormal blood glucose metabolism is considered a modifiable risk factor for CVD.
With the exception for some USPSTF recommendations involving breast cancer screening, the Affordable Care Act mandates that USPSTF recommendations with an A or B rating be covered by health insurance.
In 2008, the USPSTF gave a grade B-level recommendation to screening for type 2 diabetes in asymptomatic adults with treated or untreated hypertension (blood pressure greater than 135/80 mm Hg). They noted insufficient evidence to screen asymptomatic adults without a history of hypertension at that time.
The task force reviewed previous and new evidence on screening for type 2 diabetes, impaired fasting glucose, and impaired glucose tolerance and whether measurement of glucose resulted in improved outcomes and if interventions delayed progression to diabetes. Likewise, they wanted to know what, if any, harms could arise from screening for abnormal glucose metabolism.
The updated USPSTF recommendations call for the following:
• Screening for abnormal blood glucose in obese or overweight adults aged 40-70 years (Grade B).
• For those with abnormal glucose, referral for or offer intensive behavioral counseling on physical activity and healthful diet.
• Risk factors for abnormal glucose metabolism include physical inactivity, smoking, higher percentage of abdominal fat, overweight, and obesity. It is also often associated with other CVD risk factors such as hypertension and hyperlipidemia.
• Screening tests include: hemoglobin A1c, oral glucose tolerance test, or fasting plasma glucose with repeat testing for confirmation.
• No optimal screening interval was noted, but 3 years may be reasonable, based on previous studies.
• Interventions recommended included counseling on physical activity and a healthful diet, with insufficient evidence that medication has the same benefit to a behavioral approach.
The task force noted inadequate direct evidence that glucose measurement lessens CVD morbidity or mortality. However, they previously found evidence that intensive behavioral interventions in those at increased risk for CVD moderately lowered their CVD risk. This benefit was reported in those who are overweight or obese, have dyslipidemia, have hypertension, and/or have impaired glucose tolerance or impaired fasting glucose. Further, the task force highlighted studies that showed moderate reduction in progression to diabetes with lifestyle interventions in people with impaired glucose tolerance or impaired fasting glucose. They found that lifestyle interventions are more effective than metformin use.
Likewise, the task force noted little possible harm to initiating lifestyle intervention in order to reduce progression to diabetes and small to moderate harm in the use of drug therapy for diabetes prevention.
Furthermore, the recommendations include screening for obesity and referral to intensive behavioral interventions in those with a body mass index of 30 kg/m2 or more or a BMI greater than 25 kg/m2 and CVD risk factors.
Lifestyle interventions recommended for those at increased risk for type 2 diabetes include a combination of physical activity and dietary interventions. For example, among the effective approaches recommended are participating in individual and group sessions, setting weight loss goals, working with a trained diet or exercise counselor, and individualizing exercise or diet plans.
“The USPSTF assessed the overall benefit of screening for [impaired fasting glucose], [impaired glucose tolerance], and diabetes to be moderate. The effects of lifestyle interventions to prevent or delay progression to diabetes were consistent across a substantive body of literature.”
The USPSTF is funded by the Agency for Healthcare Research and Quality.