Table 2. Provider (n=100) Attitudes Toward Prescribing Metformin in Various Clinical Situations
Provider Attitudes Toward Metformin PrescribingProviders (%)
Patient situation 1: uncontrolled T2DMA 50-year-old patient with controlled diabetes (A1C of 6.3%), is taking metformin 500 mg daily and tolerating it well. What would you do?
    Keep 500 mg metformin/day88
    Titrate metformin to a target dose of 1500 mg/day5
    Titrate metformin to a target dose of 2000 mg/day7
Patient situation 2: uncontrolled T2DMIf a 50-year-old patient with uncontrolled diabetes and an A1C of 8.3% is taking metformin 500 mg/day and tolerating it well, which of the following would you be most likely to do?
    Titrate metformin to a target dose of 1500 mg/day11
    Titrate metformin to a target dose of 2000 mg/day84
    Add a sulfonylurea3
    Add a dipeptidyl-peptidase-4 inhibitor2
Patient situation 3: uncontrolled T2DMIf a 50-year-old patient with uncontrolled diabetes and an A1C of 7.3% is taking metformin 1500 mg/day and tolerating it well, which of the following would you be most likely to do?
    Titrate metformin to a target dose of 2000 mg per day75
    Add basal insulin0
    Add a sulfonylurea18
    Add a dipeptidyl-peptidase-4 (DPP-4) inhibitor7
Patient situation 4: chronic kidney diseaseFor a 50-year-old male patient with chronic kidney disease and diabetes taking metformin 1750 mg/day, at what point would you stop the metformin?
    When the serum creatinine is >1.551
    When the CKD-EPI eGFR is <60 mL/min15
    When the CKD-EPI eGFR is <30 mL/min33
    When the CKD-EPI eGFR is <15 mL/min or the patient is receiving dialysis1
    I would not stop the metformin0
Patient situation 5: hepatic dysfunctionFor a patient with hepatic dysfunction and diabetes taking metformin 1750 mg/day, at what point would you stop metformin or decrease the dose? (Multiple answers are acceptable)
    Elevated AST or ALT >3 times the upper limit of normal49
    Elevated INR >1.535
    Elevated bilirubin >233
    Presence of cirrhosis50
    Presence of cirrhosis with ascites60
    Hepatic steatosis present on imaging6
    I would not change the dose or stop metformin for any of these factors27
Patient situation 6: heart failureFor a patient with heart failure and diabetes taking metformin 1750 mg/day, at what point would you stop the metformin or decrease the dose?
    NYHA class I: symptoms only at activity levels that would limit normal individuals1
    NYHA class II: symptoms with ordinary exertion10
    NYHA class III: symptoms with less than ordinary exertion32
    NYHA class IV: symptoms at rest13
    I would not change the dose or stop metformin44
Patient situation 7: chronic obstructive pulmonary diseaseFor a patient with COPD and diabetes taking metformin 1750 mg/day, at what point would you stop metformin or decrease the dose? (Multiple answers are acceptable)
    Mild COPD (FEV1 >80%)0
    Moderate COPD (FEV1 50% to 80%)1
    Severe or very severe COPD (FEV1 <50%)6
    Needing oxygen chronically10
    I would not change the dose or stop metformin89
Patient situation 8: alcohol abuseFor a patient with alcoholism and diabetes taking metformin 1750 mg/day, at what point would you stop metformin or decrease the dose? (Multiple answers are acceptable)
    If they are dependent on alcohol28
    If they abuse alcohol29
    If they consume fewer than 2 drinks/day for men and 1 drink/day for women/elderly2
    If they consume >4 drinks/day or 14 drinks/week, regardless of sex or age25
    I would not change the dose or stop metformin60
Patient situation 9: history of lactic acidosisFor a 50-year-old patient with an A1C of 8.3% who is not currently taking any diabetes medications, has a remote history of lactic acidosis, and has no other risk factors for lactic acidosis, which one of the following would you do? (Multiple answers are acceptable)
    Not start metformin18
    Start metformin only25
    Start metformin and monitor serum lactic acid13
    Start metformin at a lower dose than I usually would15
    Start metformin at a lower dose than I usually would and monitor serum lactic acid26
    Start a sulfonylurea instead of metformin29
    Start a diabetes medication other than a sulfonylurea or metformin12
Patient situation 10: current lactic acidosisFor a 50-year-old patient with an A1C of 6.3%, who is only taking metformin 1750 mg/day for diabetes and who has a new diagnosis of lactic acidosis, which one of the following would you do acutely? The patient is not going to be admitted to the hospital, and their glycemia remains normal. (Multiple answers are acceptable)
    Stop metformin only54
    Stop metformin and switch to a sulfonylurea30
    Stop metformin and switch to a diabetes medication other than a sulfonylurea or metformin22
    Lower the metformin dose2
    Lower the metformin dose and monitor serum lactic acid8
    Continue metformin0
    Continue metformin and monitor serum lactic acid2
  • * Suggested answers are set in italics. For some questions, more than one answer was suggested, given that the available evidence does not suggest one correct answer.

  • ALT, alanine aminotransferase; AST, aspartate aminotransferase; CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration Equation; COPD, chronic obstructive pulmonary disease; eGFR, estimate glomerular filtration rate; FEV1, forced expiratory volume in 1 second; INR, international normalized ratio; NYHA, New York Heart Association; T2DM, type 2 diabetes mellitus.