Metformin versus DPP-4 inhibitors and risk of parkinsonism in type 2 diabetes: an active-comparator cohort study with a landmark design.
Neither common diabetes drug increases Parkinson's risk over decades, reassuring patients and doctors about long-term safety of these widely used medicines.
In the largest active-comparator study of metformin vs DPP-4i for parkinsonism risk, no primary difference was found across 785,564 person-years of follow-up after rigorous landmark design to address immortal time bias. An exploratory signal suggesting metformin benefit in 10-year survivors is interesting but likely affected by survivorship bias and should not change practice.
What the study was
- Study design
- Retrospective active-comparator cohort study with propensity score matching and landmark design (TriNetX)
- Population
- Type 2 diabetes patients initiating metformin (n=75,535) or DPP-4 inhibitors (n=75,535); TriNetX global network 2005-2025
- Sample size
- 151070
- Category
- Prevention
- Maturity
- Exploratory
- Journal
- Diabetology & metabolic syndrome
Why it surfaced
Large real-world T2DM study using rigorous landmark design addressing metformin neuroprotection hypothesis. Negative primary result is clinically informative; exploratory long-term signal warrants prospective evaluation. Well-designed RWE study.
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