M&MMetformin and Muscle in Insulin-resistant Older Veterans

Fecha de inicio: 8 de abril de 2014

Inclusion Criteria: The investigators will enroll 120 sedentary, weight-stable, ambulatory Veterans aged 65 years and older with prediabetes identified with fasting glucose values 100 mg/dL or greater but under 126 mg/dL with no use of diabetes medications. Participants must demonstrate that they are able to ambulate 400 meters without assistance. Exclusion Criteria: Chronic medical conditions affecting muscle mass or function like active non-skin cancer and hypogonadism Medications affecting muscle mass or function like glucocorticoids and androgen/antiandrogens Contraindications to metformin such as renal dysfunction defined as creatinine >= 1.5 mg/dL for men or >=1.4 mg/dL for women or estimated glomerular filtration rate (eGFR)<60 mL/min; liver dysfunction defined as alanine aminotransferase (ALT)>48 U/L, aspart aminotransferase (AST)>41 U/L or alkaline phosphatase (AlkPhos)>141 U/L; B12 deficiency defined as B12 level <180 pg/dL; congestive heart failure; known hypersensitivity to metformin; excessive alcohol intake (average of 2 or more alcoholic beverages/day over a month) For the muscle biopsy substudy, additional exclusion criteria include: Conditions that include bleeding risk such as the use of warfarin, clopidogrel/ticlopidine, aggrenox, dabigatran or anagrelide; laboratory results showing platelets<150 billion/L or international normalized ratio (INR)>1.2 or activated partial thromboplastin time (aPTT)>36 seconds Allergy to lidocaine