Metformin lowers risk of knee replacement in obese osteoarthritic patients

DELHI: Use of metformin -- a drug used for the treatment of type 2 diabetes -- is beneficial for obese patients with knee osteoarthritis (OA), suggests a recent study.

The study, published in the journal Arthritis Research & Therapy, found that such patients when given metformin, experience a slower rate of medial cartilage loss, putting them at a lower risk for total knee replacement.

Osteoarthritis is the most common form of joint disease and is the leading cause of disability and pain in older people. Metformin as a drug has the ability to modulate inflammatory and metabolic factors, leading to weight loss, inflammation reduction, and lower levels of plasma glucose and lipids. Given the biological effects of metformin, knee OA patients with the obese phenotype represent the subgroup most likely to benefit from metformin which might be a potential disease-modifying agent in knee OA.

Yuanyuan Wang, School of Public Health and Preventive Medicine, Monash University, Australia, and colleagues whether metformin use in obese patients with knee osteoarthritis is associated with a knee cartilage volume loss over 4 years and risk of total knee replacement over 6 years.

The study involved an analysis of 818 participants. The participants were divided into two groups; metformin users -- users who self-reported regular metformin use at baseline, 1-year and 2-year follow-up (n = 56) and non-users of metformin -- defined as participants who did not report the use of metformin at any visit from baseline to 4-year follow-up (n = 762).

Key findings of the study include:

• The rate of medial cartilage volume loss was lower in metformin users compared with non-users (0.71% vs. 1.57% per annum), with a difference of − 0.86% per annum, after adjustment for age, gender, BMI, pain score, Kellgren-Lawrence grade, self-reported diabetes, and weight change over 4 years.


• Metformin use was associated with a trend towards a significant reduction in risk of total knee replacement over 6 years (odds ratio 0.30, 95% CI 0.07–1.30, p = 0.11), after adjustment for age, gender, BMI, Kellgren-Lawrence grade, pain score, and self-reported diabetes.


• In addition, investigators assessed metformin’s impact on preserving knee cartilage independent of any weight loss. The beneficial effect remained, indicating that metformin’s effect on metabolic and inflammatory pathways could directly impact the rate of medial cartilage loss, as well.

"More randomized controlled trials are needed to determine whether metformin could be a disease-modifying drug for knee osteoarthritis patients who are also obese," concluded the authors.

To read the complete study follow the link: https://doi.org/10.1186/s13075-019-1915-x