Which of the following statements about biguanides is true?

BIGUANIDES Metformin and phenformin are biguanides and are preferred agents for obese patients (as these are weight neutral and may even cause weight loss). These can improve hyperiglyceridemia in obese patients. Biguanides do not stimulate the release of insulin, therefore have negligible risk of causing hypoglycemia. Metformin is: Totally excreted unchanged (without metabolism) by the kidney. Useful for polycystic ovarian disease (PCOD) First-line therapy for type 2 DM and cause maximum reduction in HbA1c levels. Most antidiabetic drugs are made to reduce microvascular complications of diabetes like nephropathy, retinopathy etc. Metformin is only oral agent to reduce macrovascular events in type 2 DM.