Joint Replacement Among Patients With T2DM: Does Metformin Matter?

Metformin use among patients with type 2 diabetes mellitus (T2DM) was associated with a significantly reduced risk of total knee or hip replacement, according to recent research.

The researchers, writing in the Canadian Medical Association Journal, “aimed to establish whether metformin use was associated with a reduced risk of total knee replacement (TKR) or total hip replacement (THR) among these patients.”

They selected patients from the Taiwan National Health Insurance Research Database diagnosed with T2DM between 2000 and 2012. “We used prescription time-distribution matching and propensity-score matching to balance potential confounders between metformin users and nonusers,” the investigators explained, and assessed the risks of joint replacement using Cox proportional hazards regression.

The final study included a total of 40,694 participants—20,347 participants who were not treated with metformin and 20,347 who were treated with metformin. The mean age was 63 years and 49.8% were women.

“Compared with participants who did not use metformin, those who used metformin had lower risks of TKR or THR (adjusted hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.60–0.81 for TKR or THR; adjusted HR 0.71, 95% CI 0.61–0.84 for TKR; adjusted HR 0.61, 95% CI 0.41–0.92 for THR) after adjustment for covariates,” the authors wrote. “Propensity-score matching analyses (10 163 participants not treated with metformin v. 10 163 treated with metformin) and sensitivity analyses using inverse probability of treatment weighting and competing risk regression showed similar results.”

The authors added that randomized controlled clinical trials of patients with osteoarthritis are warranted to determine whether metformin is effective in decreasing the need for joint replacement.

—Rebecca Mashaw

Reference:

Zhu Z, Jing-Yang Huang, Guangfeng Ruan, et al. Metformin use and associated risk of total joint replacement in patients with type 2 diabetes: a population-based matched cohort study. CMAJ. 2022;194(49)E1672-E1684 DOI: https://doi.org/10.1503/cmaj.220952