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Demographic Information Respondents (%) Clinical profession Medical resident 10 Physician, completed residency training 67 Nurse practitioner 2 Physician assistant 2 Pharmacist 19 Years practicing in clinical profession <5 years 31 5–10 years 24 11–15 years 17 >15 years 28 Geographic location Midwest (IL, IN, IA, KS, MI, MN, MO, NE, ND, OH, OK, SD, WI) 29 South (AL, AR, FL, GA, KY, LA, MS, NC, SC, TN, TX, VA, WV) 3 Mountain West (AZ, CO, NV, NM, UT, WY) 68 Type of clinic Federally qualified healthcare clinic 17 Academic clinic 61 Private clinic 5 County hospital clinic 7 Veterans affairs clinic 3 Other 7 - Table 2. Provider (n=100) Attitudes Toward Prescribing Metformin in Various Clinical Situations
Provider Attitudes Toward Metformin Prescribing Providers (%) Patient situation 1: uncontrolled T2DM A 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/day 88 Titrate metformin to a target dose of 1500 mg/day 5 Titrate metformin to a target dose of 2000 mg/day 7 Patient situation 2: uncontrolled T2DM If 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/day 11 Titrate metformin to a target dose of 2000 mg/day 84 Add a sulfonylurea 3 Add a dipeptidyl-peptidase-4 inhibitor 2 Patient situation 3: uncontrolled T2DM If 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 day 75 Add basal insulin 0 Add a sulfonylurea 18 Add a dipeptidyl-peptidase-4 (DPP-4) inhibitor 7 Patient situation 4: chronic kidney disease For 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 >1.5 51 When the CKD-EPI eGFR is <60 mL/min 15 When the CKD-EPI eGFR is <30 mL/min 33 When the CKD-EPI eGFR is <15 mL/min or the patient is receiving dialysis 1 I would not stop the metformin 0 Patient situation 5: hepatic dysfunction For 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 normal 49 Elevated INR >1.5 35 Elevated bilirubin >2 33 Presence of cirrhosis 50 Presence of cirrhosis with ascites 60 Hepatic steatosis present on imaging 6 I would not change the dose or stop metformin for any of these factors 27 Patient situation 6: heart failure For 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 individuals 1 NYHA class II: symptoms with ordinary exertion 10 NYHA class III: symptoms with less than ordinary exertion 32 NYHA class IV: symptoms at rest 13 I would not change the dose or stop metformin 44 Patient situation 7: chronic obstructive pulmonary disease For 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 chronically 10 I would not change the dose or stop metformin 89 Patient situation 8: alcohol abuse For 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 alcohol 28 If they abuse alcohol 29 If they consume fewer than 2 drinks/day for men and 1 drink/day for women/elderly 2 If they consume >4 drinks/day or 14 drinks/week, regardless of sex or age 25 I would not change the dose or stop metformin 60 Patient situation 9: history of lactic acidosis For 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 metformin 18 Start metformin only 25 Start metformin and monitor serum lactic acid 13 Start metformin at a lower dose than I usually would 15 Start metformin at a lower dose than I usually would and monitor serum lactic acid 26 Start a sulfonylurea instead of metformin 29 Start a diabetes medication other than a sulfonylurea or metformin 12 Patient situation 10: current lactic acidosis For 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 only 54 Stop metformin and switch to a sulfonylurea 30 Stop metformin and switch to a diabetes medication other than a sulfonylurea or metformin 22 Lower the metformin dose 2 Lower the metformin dose and monitor serum lactic acid 8 Continue metformin 0 Continue metformin and monitor serum lactic acid 2 * 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.
- Table 3. Provider Characteristics and Associations with Prescribing Metformin in Various Clinical Situations
Provider Characteristics Patient Scenario Odds Ratio 95% CI P Value FDR-Adjusted P Value Physicians* vs Pharmacists 1. Controlled T2DM 4.4 0.6–33.6 .1517 .4727 2. Uncontrolled T2DM, metformin 500 mg/day 0.9 0.2–3.6 .9088 .9729 3. Uncontrolled T2DM, metformin 1500 mg/day 1.5 0.5–4.6 .4614 .8057 4. Chronic kidney disease 1.2 0.4–3.4 .7746 .9683 5. Hepatic dysfunction 1.0 0.3–3.3 .9335 .9729 6. Heart failure 2.5 0.8–7.5 .1138 .4270 7. Chronic obstructive pulmonary disease 8.4 2.1–34 .0028 .1108 8. Alcohol abuse 3.4 1.2–9.6 .0229 .2663 9. History of lactic acidosis 1.4 0.5–4.4 .5353 .8236 10. Current lactic acidosis 1.5 0.5–4.1 .4438 .8057 Years practicing 1. Controlled T2DM 1.7 0.7–4 .2527 .7221 2. Uncontrolled T2DM, metformin 500 mg/day 0.6 0.4–1 .0399 .2663 3. Uncontrolled T2DM, metformin 1500 mg/day 1.1 0.8–1.7 .4990 .8057 4. Chronic kidney disease 0.7 0.5–1.1 .1174 .4270 5. Hepatic dysfunction 1.0 0.7–1.5 .9878 .9878 6. Heart failure 1.0 0.7–1.4 .9354 .9729 7. Chronic obstructive pulmonary disease 1.0 0.6–1.8 .8681 .9729 8. Alcohol abuse 1.1 0.8–1.5 .7582 .9683 9. History of lactic acidosis 1.1 0.7–1.5 .7199 .9635 10. Current lactic acidosis 1.3 0.9–1.8 .1166 .4270 Mountain West vs Midwest region 1. Controlled T2DM 1.6 0.3–10.2 .6152 .8789 2. Uncontrolled T2DM, metformin 500 mg/day 1.7 0.5–5.3 .3562 .8057 3. Uncontrolled T2DM, metformin 1500 mg/day 1.0 0.4–2.9 .9484 .9729 4. Chronic kidney disease 2.4 0.9–6.6 .0978 .4270 5. Hepatic dysfunction 0.7 0.3–1.8 .4404 .8057 6. Heart failure 1.0 0.4–2.3 .9486 .9729 7. Chronic obstructive pulmonary disease 2.6 0.7–9.9 .1536 .4727 8. Alcohol abuse 0.9 0.4–2.3 .8698 .9729 9. History of lactic acidosis 1.7 0.6–4.6 .2838 .7568 10. Current lactic acidosis 0.7 0.3–1.7 .4651 .8057 Academic vs all other settings 1. Controlled T2DM 0.4 0–3.5 .3886 .8057 2. Uncontrolled T2DM, metformin 500 mg/day 0.3 0.1–1.2 .0819 .4270 3. Uncontrolled T2DM, metformin 1500 mg/day 0.8 0.3–2.2 .7227 .9635 4. Chronic kidney disease 3.4 1.3–8.9 .0128 .2557 5. Hepatic dysfunction 1.3 0.5–3.3 .5946 .8789 6. Heart failure 2.5 1.1–5.8 .0351 .2663 7. Chronic obstructive pulmonary disease 0.6 0.1–2.2 .4032 .8057 8. Alcohol abuse 0.8 0.3–1.7 .5036 .8057 9. History of lactic acidosis 1.5 0.6–3.7 .3557 .8057 10. Current lactic acidosis 2.4 1.1–5.5 .0379 .2663 ↵* Physicians include residents and those who have completed residency training.
CI, confidence interval; FDR, false discovery rate; T2DM, type 2 diabetes mellitus.
