A large new study based on health insurance data from more than 40,000 patients with type 2 diabetes found that those who used metformin to manage high blood sugar levels were less likely to need total joint replacement.
The research, published this week in Journal of the Canadian Medical Association by scientists from China, Taiwan, and Australia, showed an association between regular use of metformin and about a 30 percent reduced likelihood of needing total knee replacement or total hip replacement. This association does not mean that metformin has been conclusively proven to cause a lower rate of joint replacements, according to the study authors.
Joint replacements are a common treatment for people with advanced osteoarthritis, a chronic joint disorder that often leaves seniors in pain and unable to walk or perform other daily functions. Diabetes has been linked to a higher risk of osteoarthritis.
In the United States, the number of total knee replacement and total hip replacement surgeries is projected to reach 572,000 per year by 2030. No medication is currently known to prevent or reverse osteoarthritis.
“The current study suggests consistent benefits of using metformin for the treatment of osteoarthritis among patients with type 2 diabetes mellitus,” says lead study author Zhaohua Zhu, PhD, associate professor at Zhujiang Hospital of Southern Medical University in China. “The findings may spur future clinical trials to test the effectiveness and efficacy of metformin in the treatment of osteoarthritis.”
Previous studies have suggested that metformin may protect against osteoarthritis in people with diabetes.
doctor Zhu and his colleagues analyzed data from the Taiwan National Health Insurance Research Database of patients with type 2 diabetes diagnosed between 2000 and 2012. The average age of those studied was 63 years, with participants almost evenly split between men and women; patients were followed for approximately 14 years. The study team noted that about 90% of total joint replacements were related to osteoarthritis.
The new research corroborates previous studies showing that metformin may provide protection against osteoarthritis. A report published in July 2022 in Scientific Reportssuggested a potential protective effect of metformin in worsening knee osteoarthritis. Another study, published in September 2022 in cellsrevealed that metformin can delay the development and progression of osteoarthritis.
Why can metformin be good for joints?
Marilyn Tan, MD, an endocrinologist at Stanford University in California who was not involved in the study, said that metformin may protect against osteoarthritis by reducing overall inflammation.
“Improved glucose control may improve the overall risk of infection and inflammation, and it’s possible that part of the decrease in inflammation contributed to lower rates of knee and hip replacement,” says Dr. Tan.
She adds, “Metformin is also generally considered a weight-neutral drug, but sometimes patients can lose weight on it, which can also help reduce the need for hip or knee replacement.”
Metformin is not yet recommended for osteoarthritis without diabetes
According to Zhu, future studies should examine the effect of metformin on osteoarthritis, particularly in overweight osteoarthritis patients.
Tan cautions that she wouldn’t go so far as to recommend metformin at this point for people who have osteoarthritis but don’t have diabetes.
“Further studies are needed to elucidate the exact mechanism of the association between metformin and joint replacement risk,” says Tan. “Metformin is not FDA-approved for use in patients without diabetes, but it would be interesting to see the effects of metformin on osteoarthritis in patients who do not have diabetes.”