A pilot study of the contraindicated use of metformin in diabetic patients with heart failure published last week in Trials has highlighted a potential discordance between the scientific community and practicing clinicians.
Metformin treatment in diabetes and heart failure: when academic equipoise meets clinical reality
T Eurich, Ross T Tsuyuki, Sumit R Majumdar, Finlay A McAlister, Richard
Lewanczuk, Marcelo C Shibata, Jeffrey A Johnson
Trials 2009, 10:12 (9 February 2009)
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The study, designed to assess the feasibility of a full-scale randomised controlled trial of metformin in this patient population, was abandoned at recruitment as all 58 patients screened failed to meet the eligibility criteria. Despite its contraindication in heart failure, 21% of screened patients were excluded due to current use of high dose metformin. More than half of the patients were receiving some level of metformin therapy.
Dr Eurich and colleagues conclude that, given the apparent confidence of clinicians in the safety and efficacy of metformin in diabetic patients with heart failure, a full-scale randomised trial would prove virtually impossible. Recent labelling changes in the United States support this conclusion, although a black box warning still exists for metformin use in this patient population.
Such a result prompts the authors to discuss the extent to which uncertainty in the scientific literature is mirrored in clinical practice, particularly given the many examples of randomised controlled trials that have changed scientific opinion, but failed to impact on the practices of individual clinicians.
Assistant Editor – Trials