Obese patients with osteoarthritis who take metformin have a slower rate of medial cartilage loss, putting them at a reduced risk for total knee replacement, a new study found.
In research published in a recent Arthritis Research & Therapy issue, investigators determined patients who take metformin, a medication traditionally used as a first-line therapy for type 2 diabetes, are at a significantly reduced risk of undergoing total knee replacement surgery long-term. This outcome, they said, could stem from metformin’s 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 osteoarthritis patients with the obese phenotype represent the subgroup most likely to benefit from metformin,” said study author Yuanyuan Wang, M.D., Ph.D., senior research fellow at Monash University in Australia.
To determine metformin’s efficacy, researchers compared medial cartilage volume loss and the incidence of total knee replacement surgery for 818 study participants, 56 of whom used the medication. Metformin recipients had a higher body mass index, experienced more knee pain, and were more likely to have diabetes.
According to study results, at a four-year follow-up, metformin recipients had a lower annual medial cartilage volume loss than other patients, 0.83 percent versus 1.55 percent, respectively. After six years, researchers analyzed the incidence of total knee replacements and determined three metformin recipients and 88 non-metformin patients underwent the procedure.
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, they said.
Ultimately, investigators said, more randomized controlled trials are needed to determine whether metformin could be a disease-modifying drug for knee osteoarthritis patients who are also obese.
Wang Y, Hussain S, Wluka A, Lim YZ, Abram F, Pelletier JP, Pelletier JM, Cicuttini, Association between metformin use and disease progression in obese people with knee osteoarthritis: data from the Osteoarthritis Initiative — a prospective cohort study, Arthritis Research & Therapy (2019), doi: 10.1186/s13075-019-1915-x.