title: The Effect of Metformin Use on Left Ventricular Ejection Fraction and Mortality Post-Myocardial Infarction.
abstract: BACKGROUND
  Animal studies showed that the use of metformin after myocardial infarction (MI) resulted in a protective effect on cardiac myocytes. In this study, we examined the effect of metformin in patients with diabetes mellitus (DM) on left ventricular ejection fraction (LVEF) and post-MI mortality.
  
  
  METHODS
  We reviewed charts of patients with MI admitted to the UAMS medical center. Baseline characteristics and 12-month follow up data were collected. Patients were classified into three groups: Control group- no DM (n = 464), Metformin group- DM + MI (n = 88) and No-Metformin group- DM + MI (n = 168). First, we compared Metformin and No-Metformin groups to the Control group. Second, we performed propensity-score matching in patients with DM, and compared Metformin to No-Metformin groups.
  
  
  RESULTS
  All-cause 30-day and 12-month mortality was significantly higher in the No-Metformin group compared to controls (13.5 vs 9.3% p = 0.03 at 30 days, 23.7 vs 15.9 % p = 0.03 at 12 months). However, all-cause 30-day and 12-month mortality were similar in the Controls and Metformin group (9.3 vs 6.8 % p = 0.93 at 30 days, 15.9 vs 11.4 % p = 0.97 at 12 months). Mean LVEF on presentation (45 % in the three groups) and at follow up (47.84, 46.38 and 43.62 % in Control, Metformin, and No-Metformin groups, respectively) were not statistically different. There were no significant differences in regard to re-hospitalization, re-intervention, new stroke, CHF development, new MI, or identifiable arrhythmias. Metformin was an independent predictor of lower 30-day and 12-month all-cause mortality in patients with DM (HR 0.25, p = 0.02 and HR 0.32, p = 0.01, respectively). In the matched analysis, 30-day all-cause mortality was significantly higher in the No-Metformin compared to the Metformin group (21.1 vs 8.8 %, p = 0.05). However the difference in 12-month all-cause mortality did not reach statistical significance (24.6 vs 15.8 %, p = 0.15).
  
  
  CONCLUSIONS
  This proof-of-concept study shows that use of metformin in patients with DM is associated with lower 30-day all-cause mortality and tendency for a lower 12-month all-cause mortality following MI without discernible improvement in LVEF.
authors.affiliation: Division of General Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA, amabualsuod@UAMS.edu.
authors.forename: Amjad
authors.initials: A
authors.lastname: Abualsuod
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Rutland
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Watts
authors.forename: Summit
authors.initials: S
authors.lastname: Pandat
authors.forename: Robert
authors.initials: R
authors.lastname: Delongchamp
authors.forename: Jawahar L
authors.initials: JL
authors.lastname: Mehta
mesh_terms: D016022:Case-Control Studies; D002423:Cause of Death; D048909:Diabetes Complications / Q000150:complications* / Q000188:drug therapy / Q000401:mortality / Q000503:physiopathology; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008687:Metformin / Q000494:pharmacology* / Q000627:therapeutic use; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000401:mortality* / Q000503:physiopathology; D013318:Stroke Volume / Q000187:drug effects*; D016277:Ventricular Function, Left / Q000187:drug effects*
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin