Background: Safety concerns limit metformin use in kidney disease. We compared major adverse cardiovascular events (MACE) for metformin or sulfonylureas users with reduced glomerular filtration rate (GFR).
Methods: A retrospective cohort combined Veterans Administration, Medicare, and National Death Index databases. Metformin or sulfonylurea users were followed from renal threshold (GFR <60 ml/min or creatinine 1.4/1.5 [female, male] mg/dL) until MACE, treatment change, loss to follow-up, non-cardiovascular death or study end. MACE included myocardial infarction, stroke, transient ischemic attack hospitalization or cardiovascular death. The analysis compared MACE hazard for metformin vs. sulfonylurea users in a matched weighted cohort accounting for competing risks of non-persistence or non-cardiovascular death.
Results: There were 67752 and 28976 persistent metformin and sulfonylurea users who reached renal threshold. The weighted cohort included 24683 metformin vs. 24801 sulfonylurea patients; 98% male; 82% white, median age 70 years (62.8, 77.8). Median GFR was 56 ml/min [51.6, 58.2] and HbA1c 6.6% [6.1, 7.1]. Metformin users had lower cause specific hazard of MACE vs. sulfonylurea (adjusted HR 0.81 [0.75, 0.87]). Subgroup results were similar by age, race and GFR.
Conclusion: Compared to sulfonylureas, metformin use in patients with reduced GFR is associated with lower MACE risk.
C. Roumie: None. J.J. Chipman: None. J. Min: None. A.M. Hung: None. A.J. Hackstadt: None. R.A. Greevy: None. C.G. Grijalva: None. T. Elasy: None. M.R. Griffin: None.
U.S. Department of Veterans Affairs (CX000570-06)
