Metformin benefits patients with type 2 diabetes and chronic comorbid disease
medwireNews: Metformin use is associated with improved outcomes among patients with type 2 diabetes and moderate chronic kidney disease (CKD), congestive heart failure (CHF), or chronic liver disease (CLD) with hepatic impairment, results of a meta-analysis suggest.
“Our findings support the recent changes in metformin labeling,” write the study authors in the Annals of Internal Medicine.
Following the decision by the US Food and Drug Administration to relax the renal contraindications for metformin use in April 2016, “an estimated 1 million additional patients with moderate CKD” became eligible to receive metformin in the USA, they add, noting that severe CKD “remains a contraindication.”
Matthew Crowley (Durham Veterans Affairs Medical Center, North Carolina, USA) and colleagues analyzed data from 17 observational studies involving between 82 and 13,930 patients that compared diabetes regimens including metformin versus regimens without metformin.
Among patients with type 2 diabetes and CKD or CHF, the meta-analysis revealed that the relative mortality risk during follow-up was 22% lower for patients receiving metformin than those not receiving it. The authors found similar results in sensitivity analyses examining studies with follow-up of 2 years or longer and studies adjusting for the propensity to receive metformin.
Metformin use was also associated with reduced all-cause mortality in patients with CLD with hepatic impairment, but the authors did not conduct a meta-analysis due to differences in outcome reporting in the three included studies.
Additionally, Crowley and team found that there were fewer hospital readmissions for heart failure with metformin-containing regimens than regimens without metformin among patients with CKD or CHF, and metformin was associated with lower rates of hypoglycemia among those with moderate CKD.
Although the researchers caution that the strength of evidence in their meta-analysis was low, they found “no evidence that the risks associated with metformin exceed those of other antihyperglycemic medications” among patients with moderate CKD, CHF, or CLD with impaired hepatic function.
They explain that most metformin trials to date have excluded patients with these chronic conditions, meaning that there is a “primary evidence gap regarding metformin use in patients with historical contraindications or precautions.”
The author of an accompanying editorial, Kasia Lipska (Yale School of Medicine, New Haven, Connecticut, USA), agrees, noting that “a better understanding of [the effects of metformin] on outcomes in contemporary practice, as well as among subgroups of patients with commonly occurring comorbid conditions, is imperative.”
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