Table 3 Effects of metformin on atrial arrhythmias: reports from clinical trials
From: Effects of metformin on atrial and ventricular arrhythmias: evidence from cell to patient
| Model | Type of study/No. of patients/follow-up | Metformin (dose/duration) | AF incidence | Interpretation | References | |
|---|---|---|---|---|---|---|
|
Taiwanese DM patients treated with metformin alone vs. other meds (mean age 58 years) | Longitudinal cohort/85,198 metformin users and 560,512 non-users/mean follow-up 5.4 years | Various dose and duration of metformin |
- ↓ AF incidence in the first 3 years after diagnosis of DM - HR of 0.81, p < 0.0001 | Metformin associated with decreased incidence of AF during the first 3 years after the diagnosis of DM | [44] | |
|
Taiwanese DM patients w/ or w/o metformin (mean age 69 years) | Nested case control study/2882 AF and 11,528 controls/mean DM duration 3.9 years |
- Various dose - At least 6 months of drug used |
- ↓ AF incidence - OR 0.81, 95%CI 0.71–0.95 | Metformin associated with decreased new onset AF | [55] | |
|
Hospitalized DM patients with AMI w/ or w/o metformin (mean age 56) | Retrospective cohort/40 Metformin alone and 705 others/28-day post AMI | Various dose |
- Metformin alone: <-> 28-day AF incidence, OR 1.1 (95%CI 0.3–4.0) - Metformin + other anti-DM drugs: ↓28-day AF incidence, OR 0.2 (95% CI 0.1–0.7) | Metformin in combination with other anti-DM drugs associated with decreased AF incidence 28-day post AMI | [56] | |
|
≥ 65 years old Taiwanese DM patients w/ or w/o metformin (mean age 73 years) | Nested case-control/1958 cases and 7832 controls/mean DM duration 8 years |
- Various dose - At least 12 months of drug used |
- <-> AF incidence - OR 1.01 (0.88–1.15) | Metformin was not associated with decreased AF incidence in elderly DM population | [57] | |
|
Patients without DM undergoing cardiac surgery randomized to metformin or placebo (mean age 65 years) | Double-blind, randomized controlled trial/57 to metformin, 57 to placebo/24-h post reperfusion | Metformin 500 mg TID for 3 days before surgery | - <-> 24-h post reperfusion Trop I level and arrhythmia | Short-term metformin pre-surgery did not decrease perioperative myocardial injury or AF in non-DM undergoing cardiac surger | [68] | |
|
DM pts undergoing cardiac surgery w/ or w/o metformin (mean age 66 years) | Retrospective matched cohort/metformin 635, non-metformin 648/post-op until hospital discharge | Metformin ≥ 500 mg any time prior to surgery |
- <-> post-op AF incidence - post-op AF 26.3% in metformin vs. 30.7% in non-metformin(p = 0.46) | Prior use of metformin in DM patients undergoing cardiac surgery was not associated with decreased post-op AF | [69] | |