Systematic review and meta-analysis of 204 studies.
81% were RCTs
Moderate-strength: metformin monotherapy -> lower long-term CV-related mortality than SU monotherapy (RR 0.65)
But, low or no evidence for differences in all-cause mortality and macro/microvascular outcomes.
DPP-4 inhibitors < metformin/SU for A1c lowering
Metformin + almost anything -> similar A1c lowering, except DPP-4 + met (not as good) and GLP-1 + met (even less good).
Weight stable or decreased on: metformin, DPP-4, GLP-1, SGLT-2s.
Weight increased with: SU, TZDs, insulin
SUs highest risk for hypoglycemia.
SGLT-2s highest risk for vaginal yeast infections.
NO INCREASED RISK for lactic acidosis with metformin!
Conclusion: metformin is still first line. Metformin contraindicated if eGFR < 30, use caution if 30-45.
Ann Intern Med 2016 Apr 19