New USPSTF Recommendations for Screening for Prediabetes and Type 2 Diabetes: An Opportunity to Create National Momentum.

Abstract

Screening for type 2 diabetes has been advocated under an assumption that an early start with preventive care will reduce risk of the multiple complications following the onset of diabetes. However, the mixed evidence for this assertion has kept diabetes screening under debate for decades and lessened its role in the public health response to diabetes. In this issue of JAMA, the US Preventive Services Task Force (USPSTF) presents its Recommendation Statement1 and an updated Evidence Review2 on screening for prediabetes and type 2 diabetes. The task force recommends that adults aged 35 to 70 years who have overweight or obesity be screened for prediabetes and type 2 diabetes and that clinicians “offer or refer patients with prediabetes to effective prevention interventions” (B recommendation). The recommendation is relatively unchanged since the 2015 USPSTF statement,3 except for the lowering of the age threshold for screening from 40 to 35 years and the addition of metformin among diabetes prevention interventions.2 Alsointhis issueofJAMA, thestudybyWangandcolleagues4 demonstrates a new high in US total age-standardized diabetes prevalence of 14% in 2015-2018 and no consistent improvements in glycemic control and risk factor management for 10 years. Along with other evidence of potential stagnation of diabetes care and outcomes,5 these findings provide important context to the new USPSTF recommendation and warrant a closer look at where the biggest missed opportunities lie and what could be gained with the new screening guidelines. The USPSTF report assessed evidence of benefit and harms of 3 interventions: population screening, early risk factor management for individuals with diagnosed diabetes, and preventive interventions for those with diagnosed prediabetes. Seeming to contradict the overall recommendation, the review concludes that there is little direct evidence that screening improves health outcomes for people with diagnosed diabetes. This conclusion relies heavily on the ADDITION study, which found no benefit of diabetes screening or detection-driven intensive risk factor management on long-term outcomes.6,7 However, the potential effects of screening, detection, and intervention for diabetes and prediabetes simultaneously, as now recommended, has not been tested in randomized trials. Thus, the rationale to screen depends on the benefits of the interventions that follow diagnosis, including the long-term attention to risk factor management and the opportunity to prevent diabetes in the large population at risk. The benefits of intervention after diabetes diagnosis still rely largely on the UK Prospective Diabetes Study Group, which almost 25 years ago showed that glycemic and blood pressure control in patients with recently diagnosed diabetes reduced risk of microvascular and macrovascular complications and, with 10 years of additional follow-up, reduced risk of myocardial infarction as well as all-cause and diabetes mortality.8 These benefits were achieved without the advantage of newer medications that have since been added to diabetes treatment guidelines (because those medications have been shown to simultaneously address metabolic, glycemic, and cardiovascular risk).9 The benefits of intervention among persons diagnosed with prediabetes relied on 23 studies from 8 countries, collectively showing a relative risk (RR) reduction in diabetes incidence associated with multicomponent prevention programs (RR, 0.78 [95% CI, 0.69-0.88]). Although this magnitude of association was less than the risk reduction reported in the 2015 report (RR, 0.53 [95% CI, 0.39-0.72]),3 it reflects an important expansion of the literature beyond the proof-of-concept diabetes prevention trials, such as the US Diabetes Prevention Program. The updated evidence review2 includes an increased number of studies, including more investigations conducted in community settings with diverse populations and longer follow-up. This, along with the scale-ups of programs seen in the US and UK, established the viability of individual-based interventions as an important approach against the diabetes epidemic.10,11 The USPSTF screening recommendations apply to a large proportion of the adult population. More than 40% of the adult population will be eligible for the screening, among whom an estimated one-third most likely will meet USPSTF criteria for a prevention program.12,13 In theory, strong implementation across the full chain of recommended actions could contribute to significant health benefits, ranging from a reduced incidence of diabetes to a reduction in diabetesrelated complications. However, surveillance data point to 3 major areas of concern that must be addressed to transform the health of the population. First, the report by Wang et al4 suggests that diabetes care has stagnated.3 Among adults with diagnosed diabetes, the overall levels of glycemic control had not improved between 2007 and 2018, less than half (48.2%) met blood pressure targets, and only 21.2% achieved the combined goal Related articles pages 704, 736, and 744 and JAMA Patient Page page 778