Metformina e insuficiencia cardiaca
Durante muchos años la metformina ha sido considerada contraindicada en el tratamiento de los diabéticos tipo 2 con insuficiencia cardiaca. El temor al desarrollo de la acidosis láctica al parecer fue exagerado, a juzgar por las investigaciones actuales. Es importante la revisión de antiguos conceptos ya que prevalece en nuestros días la idea de tratar con metformina a los diabéticos tipo 2 obesos, que son la mayoría.
Metformin May Be Safer Than Sulfonylureas in Patients With Diabetes and Heart Failure
Sept. 30, 2005 — Metformin therapy is associated with less morbidity than sulfonylurea therapy in patients with diabetes and heart failure, according to the results of a study reported in the October issue of Diabetes Care.
"Metformin is considered contraindicated in patients with heart failure because of concerns over lactic acidosis, despite increasing evidence of potential benefit," write Dean T. Eurich, BSP, MSc, from the Institute of Health Economics in Edmonton, Alberta, Canada, and colleagues. "The near absence of any cases of lactic acidosis in large observational studies and the fact that metformin levels do not correlate with lactate levels in individuals who do develop lactic acidosis supports the viewpoint that metformin may be 'an innocent bystander' in sick patients rather than a causal agent."
The average age was 72 years; 57% were male, and average duration of follow-up was 2.5 ± 2.0 years. Compared with sulfonylurea therapy, metformin therapy was associated with fewer deaths (404 [52%] for sulfonylurea monotherapy vs 69 [33%] for metformin monotherapy; hazard ratio [HR], 0.70; 95% confidence interval [CI], 0.54 - 0.91; and 263 [31%] for combination therapy [HR, 0.61; 95% CI, 0.52 - 0.72]). There was also a decrease in deaths or hospitalizations: 658 (85%) for sulfonylurea monotherapy vs 160 (77%) for metformin monotherapy (HR, 0.83; 95% CI, 0.70 - 0.99) and 681 (80%) for combination therapy (HR, 0.86; 95% CI, 0.77 - 0.96). Time to first hospitalization was not significantly different between study groups.
"Metformin, alone or in combination, in subjects with heart failure and type 2 diabetes was associated with lower morbidity and mortality compared with sulfonylurea monotherapy," the authors write. "Importantly, we also found that metformin exposure was not associated with an increase in hospitalizations, supporting the premise that it appears to be safe in this vulnerable population."
Study limitations include observational design, lack of data on subjects' glycemic control, possible selection bias, and lack of clinical or laboratory information on functional status, severity of heart failure, left ventricular function, or renal failure.
The Canadian Diabetes Association; the Heart and Stroke Foundation of Canada; The Kidney Foundation of Canada; the Canadian Institute of Health Research (CIHR) Institute of Nutrition, Metabolism and Diabetes; and the CIHR Institute of Circulatory and Respiratory Health sponsored this study. The costs of publication of this article were defrayed in part by the payment of page charges, and the article must therefore be hereby marked "advertisement" solely to indicate this fact.
Diabetes Care. 2005;28:2345-2351http://www.medscape.com/