Screening for type 2 diabetes mellitus: a systematic review for the U.S. Preventive Services Task Force.

BACKGROUND Screening for type 2 diabetes mellitus could lead to earlier identification and treatment of asymptomatic diabetes, impaired fasting glucose (IFG), or impaired glucose tolerance (IGT), potentially resulting in improved outcomes. PURPOSE To update the 2008 U.S. Preventive Services Task Force review on diabetes screening in adults. DATA SOURCES Cochrane databases and MEDLINE (2007 through October 2014) and relevant studies from previous Task Force reviews. STUDY SELECTION Randomized, controlled trials; controlled, observational studies; and systematic reviews. DATA EXTRACTION Data were abstracted by 1 investigator and checked by a second; 2 investigators independently assessed study quality. DATA SYNTHESIS In 2 trials, screening for diabetes was associated with no 10-year mortality benefit versus no screening (hazard ratio, 1.06 [95% CI, 0.90 to 1.25]). Sixteen trials consistently found that treatment of IFG or IGT was associated with delayed progression to diabetes. Most trials of treatment of IFG or IGT found no effects on all-cause or cardiovascular mortality, although lifestyle modification was associated with decreased risk for both outcomes after 23 years in 1 trial. For screen-detected diabetes, 1 trial found no effect of an intensive multifactorial intervention on risk for all-cause or cardiovascular mortality versus standard control. In diabetes that was not specifically screen-detected, 9 systematic reviews found that intensive glucose control did not reduce risk for all-cause or cardiovascular mortality and results for intensive blood pressure control were inconsistent. LIMITATION The review was restricted to English-language articles, and few studies were conducted in screen-detected populations. CONCLUSION Screening for diabetes did not improve mortality rates after 10 years of follow-up. More evidence is needed to determine the effectiveness of treatments for screen-detected diabetes. Treatment of IFG or IGT was associated with delayed progression to diabetes. PRIMARY FUNDING SOURCE Agency for Healthcare Research and Quality.