Evidence Tips the Scale Toward Screening for Hyperglycemia.

Screening and early detection for hyperglycemia is a topic of considerable interest, and there is debate as to its overall benefits (1). Policies for screening vary from the position of the American Diabetes Association (2), which recommends glucose testing in all people aged 45 years and over or at high risk for type 2 diabetes, to the position of the U.S. Preventive Services Task Force (USPSTF), which recommends only testing those with sustained hypertension (3). The USPSTF, however, is deliberating its new draft recommendations, which broaden the criteria for type 2 diabetes and prediabetes screening (http://www .uspreventiveservicestaskforce.org/Page/ Document/draft-research-plan49/screeningfor-abnormal-glucose-and-type-2-diabetesmellitus). As screening and early detection for hyperglycemia remains a topic of great interest, the article from Herman et al. (4) in this issue of Diabetes Care is timely. Specifically, Herman et al. (4) report on the beneficial effect of type 2 diabetes screening on cardiovascular (CVD) morbidity and mortality in the Anglo-Danish-Dutch Study of Intensive Treatment in Peoplewith Screen-Detected Diabetes inPrimaryCare (ADDITION-Europe) trial. Diabetes is a global problem, affecting 387 million people worldwide (5), that is growing in all countries, in urban and rural areas and projected to affect approximately 600 million individuals by 2035 (5). Type 2 diabetes (accounting for about 95%of all diabetes cases) often exists asymptomatically (6), and approximately 50% of cases globally (varying from 30% to 80% across countries) remain undiagnosed (1). Eighty percent of people with diabetes live in developing countries, and the majority of those affected are aged 40–59 years (5). In addition to the human toll of the disease by way of multiple complications (including premature mortality; heart, kidney, and eye disease; stroke; amputations; physical disability; poorer mental health; and loss of quality of life), diabetes impacts economies of individuals, families, and societies and is estimated to cost the world $612 billion annually (5). ADDITION-Europe is a randomized controlled trial assessing the effectiveness of intensive treatment compared with routine care on 5-year CVD incidence and mortality in people with screen-detected type 2 diabetes (7). Participants in the study were individuals aged 40–69 years without a previous diagnosis in the U.K., Denmark, and the Netherlands. Study results indicate that after 5.3 years of follow-up, there were no significant differences in the incidence of first CVD event between the intensive-treatment (7.2%) and the routine-care groups (8.5%) (hazard ratio 0.83 [95% CI 0.65–1.05]) (7). There were also no significant differences in allcause mortality between groups (6.2% and 6.7%, respectively; hazard ratio 0.91 [95% CI 0.69–1.21]) (7). While the ADDITION-Europe study did not show significant benefits of intensive treatment compared with routine care on CVD incidence or mortality in individuals with screen-detected diabetes, the trial was unable to answer whether there are differences in CVD outcomes in individuals with screendetected type 2 diabetes compared with those whose diabetes remains undetected and therefore untreated until time of clinical diagnosis. Given that it is not ethically feasible to conduct a trial to directly answer this question in humans, Herman et al. (4) used a validated and well-constructed computer simulation model (Michigan Model for Diabetes) to estimate the risk reductions associated with screening and intensive treatment, screening and routine treatment, and no screening with either a 3or 6-year delay in routine treatment for the management of type 2 diabetes and the prevention of CVD. Results of the simulation point to substantial benefits of screening and routine care compared with a 3-year delay in diagnosis and treatment after 5 years. Specifically,