The updated USPSTF recommends screening for prediabetes and type 2 diabetes in adults aged 35 - 75 years with conditions including overweight or obesity.
Although nearly 35% of adults in the US meeting criteria for prediabetes, there are varying risk estimates in the progression of prediabetes to diabetes. As a result, an increase in diabetes screening may ultimately improve health outcomes through earlier diagnosis and treatment.
An update to the 2015 US Preventive Services Task Force Recommendation Statement recommended screening for prediabetes and type 2 diabetes in adults aged 35 - 75 years, with conditions including overweight or obesity.
The statement effectively reduced the starting age of screening for diabetes by 5 years from the previous recommendation of 40 years old.
Evidence in favor of early diagnosis found moderate benefit in reducing all-cause mortality, diabetes-related mortality, and risk of myocardial infarction in interventions for newly diagnosed diabetes patients.
In addition, the USPSTF noted convincing evidence that preventive interventions, including lifestyle interventions, in patients with prediabetes would include a reduction in progression to type 2 diabetes (T2D). It would also show reduction in cardiovascular risk factors, including blood pressure and lipid levels.
In the updated recommendation, the USPSTF applied the statement to non-pregnant adults aged 35 - 70 years with overweight or obesity and no symptoms of diabetes, reducing the starting age of screening by 5 years.
Implementation would occur after assessment of overweight or obesity at a BMI of ≥25 and ≥30, respectively and a screening process of patients most at-risk.
The statement noted this included screening at an earlier age of patients from a demographic population with higher prevalence of diabetes, including American Indian/Alaska Native, Black, Hawaiian/Pacific Islander, Hispanic/Latino. Further, if the patient is Asian American, screening should occur at a lower BMI (≥23).
A screening test including measurement of fasting plasma glucose or HbA1c level, as well as oral glucose tolerance test.
Fasting plasma glucose level of ≥126 mg/dL, HbA1c level of ≥6.5%, or a 2-hour post-load glucose level of ≥200 mg/dL is consistent with diagnosis of T2D.
On the other hand, a fasting plasma glucose level of 100 - 125 mg/dL, HbA1c level of 5.7-6.4%, or 2-hour post-load glucose level of 140 - 199 mg/dL is consistent with prediabetes.
The investigators noted that there is uncertainty on the optimal screening interval for adults with an initial result of normal glucose level, observing a rate of every 3 years may be a reasonable approach.
Preventive interventions including lifestyle interventions that focus on diet, physical activity, or metformin have shown efficacy in delaying progression to diabetes in patients with diabetes. The use of metformin had not been approved by the US Food and Drug Administration (FDA) for this indication.
In order to update the statement, the USPSTF systematically reviewed evidence on screening for prediabetes and type 2 diabetes in asymptomatic adults, as well as preventive interventions for patients with prediabetes.
Investigators searched through databases, including PubMed and Cochrane Library, through September 2019 and continued to survey evidence until May 2021. Main outcomes included mortality, cardiovascular morbidity, diabetes-related morbidity, development of diabetes, quality of life, and harms.
The team included 89 publications (n = 68,882) in the systematic review. Data show 2 randomized clinical trials (RCTs) with 25,120 participants found no significant difference between screening and control groups in all-cause mortality at 10 years.
A total of 5 RCTs were included for recently diagnosed diabetes, including the UK Prospective Diabetes Study, which observed health outcomes improved with intensive glucose control.
Data show the relative risk of all-cause mortality was 0.87 (95% CI, 0.79 - 0.96) over 20 years of study, where intensive glucose control improved health outcomes at 10 year follow-up for overweight patients (RR 0.64; 95% CI, 0.45 - 0.91).
In addition, the evidence report found 23 RCTS showed lifestyle interventions for patients with prediabetes had reductions in the incidence of diabetes (pooled RR, 0.78; 95% CI, 0.69 - 0.88)
Other improved outcomes included reduced weight, body mass index, systolic blood pressure, and diastolic blood pressure (pooled mean difference, -1.7 mm Hg (95% CI, -2.6 -to -0.8) and -1.2 mm Hg (95% CI, -2.0 to -0.4), respectively).
In an editorial accompanying the statement, Edward W. Gregg, PhD, School of Public Health, Imperial College London, noted the recommendation remained relatively unchanged since 2015.
“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 diabetes-related complications,” Gregg and colleagues wrote.
However, they noted 3 major areas of concern in the data must be addressed in order to benefit the health of the larger population.
The first included the challenges of screening may be less important compared to the challenge of providing long-term glycemic control and sustaining CV risk factor management of patients with diabetes who live decades after diagnosis.
Next, the team noted young adults have the most to gain from the new recommendation and the most to lose by the current diabetes care delivery, while having the greatest relative increase in diabetes prevalence and lowest receipt of preventive services.
In light of this, addressing barriers to risk factor control in young adults with newly diagnosed diabetes make the group the most likely to benefit from early intervention.
Last, they observed the delivery of effective preventive interventions in patients with prediabetes is a significant factor that can be improved, with US enrollment of prevention programs representing 1% of eligible population.
“However, the greatest transformation in diabetes-related outcomes can be achieved if the problem is viewed from a longer-term perspective, whereby success is measured throughout the process and not at the beginning or the end,” they wrote.
Investigators concluded the need for further evaluations, including future studies on the effects of screening on health outcomes in patients reflective of diabetes in the United States, particularly in racial and ethnic groups.
“More US data are needed on the effects of lifestyle interventions and medical treatments for screen-detected prediabetes and diabetes on health outcomes over a longer follow-up period, particularly in populations reflective of the prevalence of diabetes,” investigators wrote.
The recommendation statement, “Screening for Prediabetes and Type 2 Diabetes US Preventive Services Task Force Recommendation Statement,” was published online in JAMA.