More than 32 million U.S. adults suffer from the condition, which most often affects the hands, the hips and the knees. There is no cure, but the discomfort is sometimes treated with corticosteroid shots. Hyaluronic acid injections are also used, although they’re less likely to be covered by insurance.

Two new unpublished studies suggest that patients who got corticosteroid shots saw their knee arthritis advance more quickly than those who didn’t.

Both studies assessed patients from the Osteoarthritis Initiative, a yearslong observational research project involving nearly 5,000 people with knee osteoarthritis. Darbandi’s research analyzed X-rays from 50 patients who got corticosteroid shots, 50 who got hyaluronic acid and another 50 in a control group. The scans, collected annually for four years, revealed worse arthritis progression among participants injected with corticosteroids compared to the other two groups.

“Knowing (faster deterioration in those using steroids) that helps patients make a more informed choice about if they want an injection and, if they do, which injection they might prefer,” said Dr. Upasana Bharadwaj, a postdoctoral researcher in UCSF’s radiology and biomedical imaging department who co-authored the study.

Dr. Jonathan Samuels, a rheumatologist at NYU Langone Health, said it’s tough to determine causation in studies like the two new ones, because many factors can influence the progression of arthritis and no two patients are the same.

Dr. Jason Kim, vice president of osteoarthritis research programs at the Arthritis Foundation, said he’d want to see studies with a “much higher sample size over a longer period of time” before considering possible causal links.

Bharadwaj and Darbandi agreed that more research is needed, as are peer reviews for their studies.

Bharadwaj noted that her team did try to control for the possibility that people who got steroid shots were simply more likely to engage in activities that furthered the progression of their arthritis afterward. To do so, they selected participants who had maintained similar activity levels throughout the study period.

Darbandi offered a few caveats to keep in mind alongside the findings. One, he said, is that the results don’t necessarily indicate the severity of symptoms patients experienced. Just because imaging shows more arthritis progression doesn’t mean a patient feels more pain. And second, he said, the results shouldn’t lead people to avoid corticosteroid shots in all situations.