Takeaway
- Even with propensity matching, metformin ever-use in patients with type 2 diabetes (T2D) is associated with a dose-dependent reduced risk of hospitalisation for heart failure (H[HF]) vs metformin never-users.
- Metformin should always be considered first-line treatment for T2D.
Why this matters
- Evidence suggests metformin is underprescribed in patients with HF.
Study design
- Population-based retrospective cohort study using Taiwan’s nationwide administrative database of newly diagnosed patients with T2D during 1999-2005, including unmatched 172,542 metformin ever-users vs 43,744 never-users and propensity score-matched pairs of 41,714 each of users and never-users, with follow-up through 2011.
- Funding: Taiwan Ministry of Science and Technology, National Science Council, Yee Fong Charity Foundation.
Key results
- Incidences of HHF for ever- vs never-users:
- Unmatched cohort: 304.15 vs 864.31 per 100,000 person-years (HR, 0.350; P<.0001);
- Matched cohort: 469.66 vs 817.01 per 100,000 person-years (HR, 0.571; P<.0001).
- Results showed consistent dose-responsive reduction in HHF risk with metformin use, especially with cumulative therapy duration >2.5 years.
- In propensity score-matched cohort created by excluding 10 potential instrumental variables, ever- vs never-users still had significantly lower risk (HR, 0.619; P<.0001).
Limitations
- Potential residual confounders.
- Retrospective data.
- Cannot use placebo with gold-standard T2D drug.
References
References