CHICAGO — Common painkillers can make the misery of osteoarthritis even worse, a new study warns.
Ibuprofen, naproxen, and diclofenac are among the many drugs for relieving aching joints. However, researchers say they may aggravate inflammation of the knee over time. They belong to a class of medications known as NSAIDS, or non-steroidal anti-inflammatory drugs. The study, based on a review of over 1,000 patients, is one of the first to investigate their long-term effects.
“To date, no curative therapy has been approved to cure or reduce the progression of knee osteoarthritis,” says lead study author Johanna Luitjens, M.D., a postdoctoral scholar in the Department of Radiology and Biomedical Imaging at the University of California-San Francisco, in a media release.
“NSAIDs are frequently used to treat pain, but it is still an open discussion of how NSAID use influences outcomes for osteoarthritis patients. In particular, the impact of NSAIDs on synovitis, or the inflammation of the membrane lining the joint, has never been analyzed using MRI-based structural biomarkers.”
Arthritis patients do better without the painkillers
The team found no benefit in 277 patients with moderate to severe osteoarthritis who also engaged in sustained NSAID use. In fact, joint inflammation and cartilage quality got worse over the next four years compared to a group of 793 controls who did not take the drugs.
Dr. Luitjens and her colleagues looked at the link between NSAIDs and synovitis and assessed how the therapy impacted joint structure over time.
“Synovitis mediates development and progression of osteoarthritis and may be a therapeutic target,” Dr. Luitjens continues. “Therefore, the goal of our study was to analyze whether NSAID treatment influences the development or progression of synovitis and to investigate whether cartilage imaging biomarkers, which reflect changes in osteoarthritis, are impacted by NSAID treatment.”
All participants underwent 3T MRI imaging of their knees at the start and end of the study period. This scan generates a magnetic field twice as strong as normal magnetic resonance imaging. Scans were scored for cartilage thickness, composition, and other measurements that served as non-invasive biomarkers of inflammation and arthritis progression.
“In this large group of participants, we were able to show that there were no protective mechanisms from NSAIDs in reducing inflammation or slowing down progression of osteoarthritis of the knee joint,” the study author reports. “The use of NSAIDs for their anti-inflammatory function has been frequently propagated in patients with osteoarthritis in recent years and should be revisited, since a positive impact on joint inflammation could not be demonstrated.”
1 in 4 deal with some form of arthritis
The CDC reports that about one in four U.S. adults (23.7%) or about 58.5 million people have a diagnosed case of arthritis. There are several possible reasons why NSAIDs increase synovitis.
“On the one hand, the anti-inflammatory effect that normally comes from NSAIDs may not effectively prevent synovitis, with progressive degenerative change resulting in worsening of synovitis over time,” Dr. Luitjens concludes. “On the other hand, patients who have synovitis and are taking pain-relieving medications may be physically more active due to pain relief, which could potentially lead to worsening of synovitis, although we adjusted for physical activity in our model.”
The study leader is calling for prospective, randomized studies to provide conclusive evidence of the anti-inflammatory impact of NSAIDs. Osteoarthritis is the most common form of arthritis, affecting more than 32 million adults in the U.S. and more than 500 million worldwide.
It occurs most frequently in the hands, hips, and knees. In patients, the cartilage that cushions the joint gradually wears away. Arthritis is often accompanied by inflammation, or swelling, of the joint, which can be extremely painful.
The study authors presented their findings at the annual meeting of the Radiological Society of North America (RSNA).
South West News Service writer Mark Waghorn contributed to this report.