Variations in Metformin Prescribing for Type 2 Diabetes

Abstract

BACKGROUND: Reasons for suboptimal metformin prescribing are unclear, but may be due to perceived risk of lactic acidosis. The purpose of this study is to describe provider attitudes regarding metformin prescribing in various patient situations. METHODS: An anonymous, electronic survey was distributed electronically to 76 health care providers across the nation. The 14-item survey contained demographic questions and questions related to prescribing of metformin for T2DM in various patient situations, including suboptimal glycemic control, alcohol use, history of lactic acidosis, and varying degrees of severity for certain health conditions, including renal and hepatic dysfunction, chronic obstructive pulmonary disease, and heart failure. RESULTS: There were a total of 100 respondents. For suboptimal glycemic control, most providers (75%) would increase metformin from 1500 to 2000 mg daily; however, 25% would add an alternate agent, such as a sulfonylurea (18%) or dipeptidyl peptidase-4 inhibitor (7%). Although 51% of providers would stop metformin based on serum creatinine thresholds, the remainder would rely on glomerular filtration rate thresholds of <60 mL/min (15%), <30 mL/min (33%), or <15 mL/min (1%) to determine when to stop metformin. For heart failure, 45% of providers would continue metformin as currently prescribed regardless of severity. Most providers would adjust metformin for varying severity of hepatic dysfunction (74%) and alcohol abuse (40%). CONCLUSIONS: Despite evidence supporting the cardiovascular benefits of metformin, provider attitudes toward prescribing metformin are suboptimal in certain patient situations and vary greatly by provider.