Diabetic CKD: metformin tops sulfonylureas for survival

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  • Initiation of metformin rather than a sulfonylurea reduces mortality risk in patients with type 2 diabetes (T2DM) and chronic kidney disease (CKD).

Why this matters

  • Patients with moderately-severely reduced estimated glomerular filtration rate (eGFR) experienced the largest risk reduction.
  • Findings support FDA guidance to consider metformin in patients with eGFR between 45 and 59 mL/min/1.73 m2.

Study design

  • Veterans Health Administration study of 175,296 patients with CKD, followed ≥1 year before initiating metformin (52.4%) or sulfonylurea (47.6%) monotherapy during 2004-2009.
  • Funding: National Heart, Lung, and Blood Institute.

Key results

  • Mean monotherapy duration was 1.7 years; 22.6% and 28.8% of metformin- and sulfonylurea-treated patients later added a second agent.
  • 5121 patients died during follow-up.
  • Metformin yielded a 36% reduction in mortality risk vs sulfonylureas (HR, 0.64; 95% CI, 0.60-0.68).
  • Among patients with eGFR ≥90 mL/min/1.73 m2, metformin reduced mortality risk by 41% (HR, 0.59; 95% CI, 0.50-0.70).
  • A smaller effect was observed with eGFR between 45 and 59 mL/min/1.73 m2 (HR, 0.80; P<.001).
  • The greatest absolute risk difference occurred among patients with eGFR between 30 and 44 mL/min/1.73 m2 (12.1 fewer deaths/1000 person-years [PY]).
  • Risk differences with eGFR of ≥90, 60-89, and 45-59 mL/min/1.73 m2 were 3.0, 4.3, and 3.4 fewer deaths/1000 PY, respectively.


  • Observational data, reliance on ICD-9 codes.