Metformin fails to prevent diabetes in non-diabetic cardiovascular patients: Systematic review and meta-analysis

Table 6 Grading of Recommendations, Assessment, Development, and Evaluation evaluation of overall evidence of studies according to analyses

Metformin compared to placebo for T2DM prevention
Patient or population: Patients with CAD without T2DM; settings: Randomized controlled trials; intervention: Metformin; comparison: Placebo
Outcomes	Illustrative comparative risks1 (95%CI)		Relative effect (95%CI)	No of participants (studies)	Quality of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	Placebo	Metformin
T2DM	Study population		OR: 0.97 (0.65-1.45)	933 (4 studies)	Very low
	123 per 1000	120 per 1000 (84-169)

¹The basis for the assumed risk (e.g., the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% confidence interval). Grading of Recommendations, Assessment, Development, and Evaluation Working Group grades of evidence high quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. T2DM: Type-2 diabetes mellitus; CAD: Coronary artery disease; CI: Confidence interval; OR: Odds ratio; GRADE: Grading of Recommendations, Assessment, Development, and Evaluation.