Screening for prediabetes and type 2 diabetes

Abstract

ImportanceType 2 diabetes is common and is a leading cause of morbidity and disability. ObjectiveTo review the evidence on screening for prediabetes and diabetes to inform the US Preventive Services Task Force (USPSTF). Data SourcesPubMed/MEDLINE, Cochrane Library, and trial registries through September 2019; references; and experts; literature surveillance through May 21, 2021. Study SelectionEnglish-language controlled studies evaluating screening or interventions for prediabetes or diabetes that was screen detected or recently diagnosed. Data Extraction and SynthesisDual review of abstracts, full-text articles, and study quality; qualitative synthesis of findings; meta-analyses conducted when at least 3 similar studies were available. Main Outcomes and MeasuresMortality, cardiovascular morbidity, diabetes-related morbidity, development of diabetes, quality of life, and harms. ResultsThe review included 89 publications (N=68882). Two randomized clinical trials (RCTs) (25120 participants) found no significant difference between screening and control groups for all-cause or cause-specific mortality at 10 years. For harms (eg, anxiety or worry), the trials reported no significant differences between screening and control groups. For recently diagnosed (not screen-detected) diabetes, 5 RCTs (5138 participants) were included. In the UK Prospective Diabetes Study, health outcomes were improved with intensive glucose control with sulfonylureas or insulin. For example, for all-cause mortality the relative risk (RR) was 0.87 (95% CI, 0.79 to 0.96) over 20 years (10-year posttrial assessment). For overweight persons, intensive glucose control with metformin improved health outcomes at the 10-year follow-up (eg, all-cause mortality: RR, 0.64 [95% CI, 0.45 to 0.91]), and benefits were maintained longer term. Lifestyle interventions (most involving >360 minutes) for obese or overweight persons with prediabetes were associated with reductions in the incidence of diabetes (23 RCTs; pooled RR, 0.78 [95% CI, 0.69 to 0.88]). Lifestyle interventions were also associated with improved intermediate outcomes, such as reduced weight, body mass index, systolic blood pressure, and diastolic blood pressure (pooled weighted 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). Metformin was associated with a significant reduction in diabetes incidence (pooled RR, 0.73 [95% CI, 0.64 to 0.83]) and reduction in weight and body mass index. Conclusions and RelevanceTrials of screening for diabetes found no significant mortality benefit but had insufficient data to assess other health outcomes; evidence on harms of screening was limited. For persons with recently diagnosed (not screen-detected) diabetes, interventions improved health outcomes; for obese or overweight persons with prediabetes, interventions were associated with reduced incidence of diabetes and improvement in other intermediate outcomes.This systematic review to support the 2021 US Preventive Services Task Force Recommendation Statement on screening for diabetes summarizes published evidence on the benefits and harms of screening for and treatment of prediabetes and type 2 diabetes in asymptomatic persons.