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Kidney Week

Abstract: FR-PO245

A Safety Comparison of Metformin vs. Sulfonylurea Initiation in Patients with Type 2 Diabetes and CKD: A Retrospective Cohort Study

Session Information

Category: Diabetic Kidney Disease

  • 602 Diabetic Kidney Disease: Clinical


  • Whitlock, Reid, Seven Oaks Hospital Chronic Disease Innovation Centre, Winnipeg, Manitoba, Canada
  • Hougen, Ingrid, University of Manitoba, Winnipeg, Manitoba, Canada
  • Komenda, Paul, Seven Oaks Hospital Chronic Disease Innovation Centre, Winnipeg, Manitoba, Canada
  • Rigatto, Claudio, Chronic Disease Innovation Centre, Winnipeg, Manitoba, Canada
  • Clemens, Kristin, Western University, London, Ontario, Canada
  • Tangri, Navdeep, Seven Oaks Hospital Chronic Disease Innovation Centre, Winnipeg, Manitoba, Canada

Metformin is the initial oral antihyperglycemic agent of choice in most patients with type 2 diabetes (T2D). However, in patients with chronic kidney disease (CKD), guidelines often recommend that metformin not be used due to slower clearance and risk of lactic acidosis. Sulfonylureas are a common alternative to metformin but have been associated with hypoglycemia, weight gain and cardiovascular events. We sought to compare the safety of metformin versus sulfonylureas in patients with T2D by CKD stage.


This retrospective cohort study included adults in Manitoba, Canada with T2D, an incident monotherapy prescription for metformin or a sulfonylurea, and a serum creatinine measurement from April 2006 to March 2017. Patients were stratified by estimated glomerular filtration rate (eGFR) into the following groups: eGFR ≥90, 60-89, 45-59, 30-44 or <30 ml/min/1.73 m2. Outcomes included all-cause mortality, cardiovascular events, and major hypoglycemic episodes. Baseline characteristics were used to calculate propensity scores and perform inverse probability of treatment weights analysis and eGFR group was examined as an effect modifier for each outcome.


The cohort consisted of 21,996 individuals (19,990 metformin users and 2,006 sulfonylurea users). Metformin use was associated with a lower risk of all-cause mortality (HR 0.48, 95% CI 0.40-0.58, p<0.001), cardiovascular events (HR 0.67, 95% CI 0.52-0.86, p=0.002), and major hypoglycemic episodes (HR 0.14, 95% CI 0.09-0.20, p<0.001), when compared to sulfonylureas. CKD was a significant effect modifier for all-cause mortality (p=0.002), but not for cardiovascular events or major hypoglycemic episodes.


Sulfonylurea monotherapy is associated with a higher risk of all-cause mortality, major hypoglycemic episodes and cardiovascular events compared to metformin. Although the presence of CKD attenuated the mortality benefit, metformin may be a safer alternative to sulfonylureas in patients with CKD.


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