Efficacy and effectiveness of screen and treat policies in prevention of type 2 diabetes: systematic review and meta-analysis of screening tests and interventions.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of diagnostic accuracy studies and intervention trials.
PubMed 28052845 · doi:10.1136/bmj.i6538
What was done
A systematic review and meta-analysis across Medline, PreMedline, and Embase evaluating the diagnostic accuracy of screening tests for pre-diabetes (against the oral glucose tolerance test standard) and the efficacy of lifestyle or metformin interventions in preventing progression to type 2 diabetes. The review analyzed 49 screening test studies and 50 controlled intervention trials.
What was found
HbA1c demonstrated a mean sensitivity of 0.49 (95% CI 0.40 to 0.58) and specificity of 0.79 (95% CI 0.73 to 0.84) for pre-diabetes detection. Fasting plasma glucose showed a mean sensitivity of 0.25 (95% CI 0.19 to 0.32) and specificity of 0.94 (95% CI 0.92 to 0.96). 47% of individuals with abnormal HbA1c had no other glycemic abnormality. Lifestyle interventions reduced the relative risk of type 2 diabetes by 36% (95% CI 28% to 43%) over 6 months to 6 years, attenuating to 20% (95% CI 8% to 31%) during post-trial follow-up. Specific quantitative results for metformin were not reported in the abstract.
Why it matters
Common screening tests for pre-diabetes frequently miss individuals or yield false positives, significantly attenuating the population-level impact of effective preventive lifestyle interventions.
Limits
Diagnostic threshold cut-offs varied across the included primary screening studies. The total number of individual participants and quantitative outcomes for metformin were not reported in the abstract. Interventions evaluated under trial conditions may not reflect real-world implementation or adherence.
Cited by
- supports Hemoglobin A1C testing misses more than half of prediabetes and diabetes cases.
- supports Fasting glucose testing misses more than half of prediabetes and diabetes cases.