Screening asymptomatic adults for type 2 diabetes does not improve all-cause or cardiovascular mortality, according to a report published online April 13 in Annals of Internal Medicine.
An estimated 8 million asymptomatic adults are thought to have undiagnosed type 2 diabetes in the United States. In a systematic review of the literature since 2007, investigators for the U.S. Preventive Services Task Force found that screening for the disease, even when it leads to intensive interventions to decrease blood glucose, improve lipid profiles, and reduce blood pressure, fails to reduce 10-year mortality.
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The USPSTF is now taking public comments on its findings and will finalize its recommendations on diabetes screening in the near future, said Dr. Shelley Selph, lead author of this report as well as professor of medical informatics and clinical epidemiology at Oregon Health & Sciences University, Portland, and her associates.
To update its 2008 recommendations on diabetes screening, the USPSTF reviewed the literature for relevant randomized, controlled trials; controlled observational studies; and systematic reviews published since then. The 2008 recommendations cited insufficient evidence to assess the balance of benefits and harms of screening asymptomatic adults unless they had elevated blood pressure.
Since then, two large, good-quality trials demonstrated that screening was not superior to no screening in reducing overall mortality. A third large, fair-quality trial showed that an intensive, multifactorial intervention failed to improve all-cause or cardiovascular mortality. And nine systematic reviews examining type 2 diabetes that was not specifically screen detected showed that intensive glucose control failed to reduce all-cause or cardiovascular mortality.
One trial deemed to be of fair quality found that, compared with not screening for type 2 diabetes, screening failed to reduce the risk of cardiovascular mortality (hazard ratio, 1.02), cancer mortality (HR, 1.08), or diabetes-related mortality (HR, 1.26), according to Dr. Selph and her associates (Ann. Intern. Med. 2015 April 13 [doi:10.7326/M14-2221]).
In addition, numerous other trials assessing outcomes after treatment of impaired fasting glucose or impaired glucose tolerance also consistently found no effect on all-cause or cardiovascular mortality. However, 16 trials found that this approach did delay progression to diabetes.
“There is also little evidence on the effect of screening in ethnic and racial minorities, in whom the prevalence of diabetes is greater than in persons of white, European ancestry,” Dr. Selph and her associates noted.