Pain relievers may worsen arthritis inflammation, study finds

Osteoarthritis is the most common form of arthritis


Taking certain anti-inflammatory pain relievers for osteoarthritis may worsen inflammation in the knee joint over time, according to a study.

Osteoarthritis is the most common form of arthritis, affecting more than 500 million people worldwide. It occurs most frequently in the hands, hips and knees.

In people with osteoarthritis, the cartilage that cushions the joint gradually wears away. Arthritis is often accompanied by inflammation, or swelling, of the joint, which can be painful.

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly prescribed for osteoarthritis pain and inflammation. However, little is known of the long-term effects of these drugs on disease progression.

"To date, no curative therapy has been approved to cure or reduce the progression of knee osteoarthritis, said the study's lead author, Johanna Luitjens, postdoctoral scholar at the University of California, San Francisco, US.

"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 analysed using MRI-based structural biomarkers," Luitjens said.

In the study, being presented next week at the annual meeting of the Radiological Society of North America (RSNA), the researchers analysed the association between NSAID use and synovitis in patients with osteoarthritis of the knee and to assess how treatment with NSAIDs affects joint structure over time.

"Synovitis mediates development and progression of osteoarthritis and may be a therapeutic target," Luitjens said.

"Therefore, the goal of our study was to analyse 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," the scientist said.

For the study, 277 participants from the Osteoarthritis Initiative cohort with moderate to severe osteoarthritis and sustained NSAID treatment for at least one year between baseline and four-year follow-up were included in the study and compared with a group of 793 control participants who were not treated with NSAIDs.

All participants underwent MRI of the knee initially and after four years. Images were scored for biomarkers of inflammation.

Cartilage thickness, composition and other MRI measurements served as noninvasive biomarkers for evaluating arthritis progression. The results showed no long-term benefit of NSAID use.