Screening Asymptomatic Adults for Type 2 Diabetes May Not Improve Mortality

Screening asymptomatic adults for type 2 diabetes does not appear to reduce mortality, but it does lead to earlier treatment of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) and delayed progression to diabetes.

In a recent issue of the Annals of Internal Medicine, the U.S. Preventive Services Task Force (USPSTF) published a systematic evidence review to inform an upcoming update of task force recommendations on screening asymptomatic, nonpregnant adults for type 2 diabetes.¹

“Given the increasing prevalence of abnormal glucose metabolism in the U.S. population, the USPSTF sought to examine the benefits and harms of screening for IFG, IGT and type 2 diabetes. The task force is not considering the costs of providing a service in this assessment,” said task force member Michael Pignone, MD, MPH, who is a professor of medicine and chief of the division of general internal medicine at University of North Carolina at Chapel Hill.

Approximately 21 million persons in the U.S. received a diabetes diagnosis in 2010 and, in that same year, 8.1 million people (27.8%) with diabetes reportedly went undiagnosed, according to background information in the review. Screening asymptomatic persons for diabetes may lead to earlier identification and earlier or more intensive treatments, which some suggest may improve health outcomes. 

To assess the benefits and harms of screening for type 2 diabetes, IFG or IGT among asymptomatic adults, the researchers reviewed studies published from 2007 to October 2014.

Potential Benefits?

The evidence suggests that screening asymptomatic, nonpregnant adults for type 2 diabetes could help in delaying progression to the disease by identifying those who could benefit from treatment of IFG and IGT. Nevertheless, screening did not improve mortality rates after 10 years of follow-up.

“If you diagnose prior to the development of diabetes and you treat them, then you can delay or prevent diabetes and that is an important finding,” lead author Shelley Selph, MD, MPH, who is an assistant professor of medical informatics and clinical epidemiology at Oregon Health & Science University in Portland, said in an interview with Endocrinology Advisor.

In two trials — the Anglo-Danish-Dutch Study of Intensive Treatment in People With Screen Detected Diabetes in Primary Care (ADDITION) and the Ely study — screening for diabetes was associated with no 10-year mortality benefit, as compared with no screening.

Similarly, most of the trials of treatment of IFG or IGT demonstrated no effect on all-cause or cardiovascular (CV) mortality.

In one trial, lifestyle modification was associated with decreased risk for both all-cause and CV mortality after 23 years, according to the review.

The review also showed no effect of an intensive multifactorial intervention on risk for all-cause or CV mortality vs. standard control for screen-detected diabetes.

In diabetes that was not specifically screen-detected, nine systematic reviews demonstrated intensive glucose control was not associated with a reduced risk for all-cause or CV mortality.

Data from 16 trials, however, consistently showed that treatment of IFG or IGT was associated with delayed progression to diabetes.