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The medication metformin is often prescribed to help treat type 2 diabetes. Francis J Dean/Shutterstock
  • Researchers are reporting that the type 2 diabetes drug metformin can help reduce the need for knee or hip joint replacement in people with the condition.
  • The researchers said there are several possible reasons for metformin reducing the risk for joint replacement surgery, including a reduction in inflammation and better-regulated metabolism.
  • Joint replacement surgery is often the result of osteoarthritis.

Metformin, a drug often prescribed for type 2 diabetes, can significantly reduce the risk of knee or hip joint replacement for people with osteoarthritis, according to a study published today by researchers from China, Taiwan, and Australia in the Canadian Medical Association Journal.

The researchers analyzed data from the Taiwan National Health Insurance Research Database, comparing people who took metformin for type 2 diabetes to people diagnosed with diabetes who were not taking it.

They specifically looked at the risk of either a total knee or a total hip replacement.

Researchers identified 40,694 participants from the database who had been diagnosed with type 2 diabetes between 2000 and 2012. Half of these individuals had been treated with metformin while the other half had not. The scientists followed the health outcomes of the participants for 14 years. The average age of the participants was 63. Half were men and half were women.

During the study period, 837 participants had a total knee replacement and 148 had a total hip replacement. Researchers reported that 90 percent of the joint replacements were due to osteoarthritis.

The use of metformin was associated with a lower incidence of either a knee or hip replacement.

The researchers noted several possible reasons for the reduction of joint replacement risk, including reduced inflammation and better-regulated metabolism.

“This is a great study with exciting findings,” said Dr. Medhat Mikhael, a pain management specialist and medical director of the non-operative program at the Spine Health Center at MemorialCare Orange Coast Medical Center in California. “Diabetes is a major risk factor for osteoarthritis and most studies show that patients with insulin-resistance diabetes are more prone to the development of it.”

“I believe it’s [metformin’s] anti-inflammatory and chondroprotective effects that help reduce the synovitis and cartilage degradation,” Mikhael told Healthline. “I also believe that the control of diabetes through glucose lowering and improving insulin resistance allow patients to perform proper exercises, so they lose weight in addition to the weight loss that metformin offers.”

Experts add, however, that this study is preliminary and additional studies are needed to analyze the findings further.

“This is a large study but only demonstrates some correlation without any causation at this point,” said Dr. Adam Rivadeneyra, a sports medicine physician with the Hoag Orthopedic Institute in California.

“Osteoarthritis is such a large-scale problem that it would be wonderful to identify different treatment options that might help decrease symptoms and the need for surgical treatments,” Rivadenevra told Healthline. “At this time, a randomized controlled trial would be beneficial to see if metformin reduces pain. There’s still a lot we don’t know about osteoarthritis and the pain it causes. Similarly, we don’t know much about the mechanisms of many medications for ‘off-label’ uses. Overall, ‘I don’t know how this would benefit my patients’ fits this scenario pretty well at the moment.”

Osteoarthritis is the most common form of arthritis, affecting more than 32 million adults in the United States. It most frequently occurs in the hands, hips, and knees, according to the Centers for Disease Control and Prevention.

In osteoarthritis, the cartilage in a joint is degraded and bones rub against one another. The disease usually develops slowly but continues to progress.

Currently, there is no treatment that can reverse the joint damage.

Symptoms include:

  • Pain
  • Stiffness
  • Swelling
  • Reduced function or range of motion in the joint

Some treatments include:

  • Physical activity
  • Physical therapy with muscle-strengthening exercises
  • Weight loss
  • Pain relievers
  • Supportive devices such as crutches or canes

Diabetes and insulin resistance are risk factors for osteoarthritis.

Metformin is often used to treat type 2 diabetes and insulin resistance. The scientists in the recent study note that metformin is associated with a reduced risk for cardiovascular and other inflammatory diseases.

Surgery, such as joint replacement, might be suggested for osteoarthritis if other treatment options have not provided relief.

In joint replacement surgery, parts of a damaged joint are removed and replaced with metal, plastic, or ceramic prosthesis, according to the American Academy of Orthopedic Surgeons.

The most common types are knee and hip replacements. Other joints, such as the ankle, wrist, shoulder, or elbow, are replaced but not as often.

The researchers for the recent study noted that total joint replacements could reach 572,000 annually by 2030.

The past few years have brought new developments in managing type 2 diabetes, including continuous glucose monitors and new drugs such as sodium-glucose cotransporter-2 (SGLT-2) inhibitors.

These drugs help the kidneys remove sugar from the blood.

There are also ways you can reduce your chances of developing type 2 diabetes or better manage blood sugars.

Some of the top ways to prevent type 2 diabetes are to:

  • Eat a balanced diet
  • Get regular exercise
  • Take steps to manage your weight, if needed

Caroline Thomason, a dietitian based in Virginia who helps women with dieting and finding confidence with food, offers the following tips for managing your blood sugar:

Lastly, talk to your doctor to make sure other medications you are taking do not raise blood sugar levels