Osteoarthritis (OA) risk may be influenced by metabolic factors in individuals with type 2 diabetes mellitus (T2DM), yet real-world data on metformin’s potential joint-related effects remain limited. A retrospective cohort study published in Diabetes Research and Clinical Practice evaluated the association between metformin use and risk of OA development or need for total knee replacement (TKR) in adults with T2DM.

The analysis used electronic health records from January 2015 to December 2021 in a large healthcare database. A total of 362,091 adults with T2DM were identified, including 244,562 metformin users and 117,529 non-users. Multivariable-adjusted Cox proportional hazards models were used to assess incident OA and TKR risk. Propensity score matching and competing risk regression were performed to minimize confounding.

During follow-up, 28,724 incident OA cases and 1,593 TKR procedures were recorded. Metformin use was associated with a modest reduction in OA risk compared with non-use (adjusted HR 0.95; 95% CI, 0.92-0.96; p < 0.001). No significant difference in TKR risk was observed between groups (adjusted HR 1.05; 95% CI, 0.94-1.18; p = 0.352).

These findings indicate that metformin use was associated with modestly lower OA incidence but not with reduced TKR risk in adults with T2DM.