A systematic review has been conducted by Crowley MJ et al. with a purpose to synthesize data addressing outcomes of metformin use in populations with type 2 diabetes and moderate to severe chronic kidney disease (CKD), congestive heart failure (CHF), or chronic liver disease (CLD) with hepatic impairment. The results published in Annals of Internal Medicine concludes that Metformin use in patients with moderate CKD, CHF, or CLD with hepatic impairment is associated with improvements in key clinical outcomes.
When approved in 1994, metformin was contraindicated in the setting of chronic kidney disease (CKD) and in those with conditions that may promote lactate accumulation, such has congestive heart failure (CHF). However, recent changes to the U.S. FDA boxed warning for metformin that loosen these restrictions will increase its use in subgroups of patients with type 2 diabetes in whom it was previously contraindicated. Crowley et al sought to synthesize data addressing outcomes of metformin use in populations with type 2 diabetes and moderate to severe CKD (with estimated glomerular filtration rate less than 60 mL/min/1.73 m2), CHF, or chronic liver disease (CLD) with hepatic impairment.
Data was pooled from 17 observational studies published between January 1994 and September 2016 that: 1) examined adults with type 2 diabetes and CKD, CHF, or CLD with hepatic impairment; compared diabetes regimens that included metformin with those that did not; and reported on all-cause mortality, major adverse cardiovascular events, and other outcomes of interest.
The authors concluded that, “On the basis of the available evidence, we found metformin therapy seems to be associated with reduced all-cause mortality among patients with moderate CKD, CHF, or CLD with impaired hepatic function; fewer CHF readmissions among those with moderate CKD or CHF; and a lower hypoglycemia rate among those with moderate CKD.”
These findings support the recent changes in metformin labeling, although the data on multiple outcomes of interest were sparse and the strength of evidence was low, said the authors.