Metformin and incident osteoarthritis: Causal insights from a co-twin control study
Authors' conclusion
Starting metformin treatment may be associated with a decreased risk of incident diagnosis of OA in specialist care over an 11-year follow-up period. The 10-year cumulative incidence was ∼3 percentage points lower among metformin initiators than non-initiators.
Study context
- Population
- Twins aged 35–75 years living in Sweden on December 31st 2005, without prior osteoarthritis (OA) diagnosis and no prior metformin treatment1,261 discordant pairs
- Comparison
- Metformin initiation vs non-treated co-twin
- Outcome
- Incident OA in any joint as diagnosed in specialist care
- Follow-up
- Up to 11 years
Methodological detailsdiscordant twin pairs, stratified Cox model, within-between Weibull shared frailty model, adjusted for age, sex, education level, body mass index (BMI) and smoking
- Discordant twin pairs
- Stratified Cox model
- Within-between Weibull shared frailty model
- Adjusted for age, sex, education level, BMI and smoking
Main finding
As reported in the abstract
Incident OA · 11-year follow-up
Estimate (95% CI)
Treatedvs Non-treated
crude HR 0.86(0.62–1.19)
Treatedvs Non-treated
aHR 0.60(0.44–0.82)
Further findings
| Outcome | Treated twins | Non-treated twins | Difference (%) (95% CI) | |
|---|---|---|---|---|
| Cumulative incidence of OA · 10 years | 6.7% (95% CI 4.8–8.6) | 9.7% (95% CI 9.3–10.1) | −3.1 (−5.1- (−1.1)) | |
| −10−505Difference, % (linear scale) |
Original publication
Metformin and incident osteoarthritis: Causal insights from a co-twin control study. Osteoarthritis Cartilage. Published 18 December 2025. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →