. Author manuscript; available in PMC: 2018 Feb 7.

Published in final edited form as: Ann Intern Med. 2017 Jan 3;166(3):191–200. doi: 10.7326/M16-1901

Table 1.

Overall strength of evidence regarding key outcomes associated with metformin use among patients with moderate-to-severe CKD and CHF

Outcome	# Studies (Patients)	Findings	SOE Rationale by Domain
Patients with moderate-to-severe CKD
All-cause mortality	5 observational (33,442)	HR 0.77 (95% CI 0.61 to 0.97) 48 fewer deaths/1,000 (81 to 6 fewer)	Low SOE Moderate ROB, Inconsistent, Precise, Direct
Patients with CHF
All-cause mortality	11 observational (35,410)	HR 0.78 (95% CI 0.71 to 0.87) 48 fewer deaths/1,000 (64 to 29 fewer)	Low SOE Moderate ROB, Consistent, Precise, Direct
Cardiovascular mortality	3 observational (6,468)	HR 0.77 (0.53 to 1.12) 66 fewer deaths/1,000 (136 fewer to 35 more)	Insufficient SOE Moderate ROB, Consistent, Imprecise, Direct
CHF readmission	4 observational (26,510)	HR 0.87 (95% CI 0.78 to 0.97) 12 fewer readmissions/1,000 (20 to 3 fewer)	Low SOE Low ROB, Consistent, Precise, Direct

Abbreviations: CHF=congestive heart failure; CKD=chronic kidney disease; HR=hazard ratio; ROB=risk of bias; SOE=strength of evidence