This study was published in the journal Arthritis Care & Research in July 2021, a publication of the American College of Rheumatology. It examined patient input from 2014 and 2019 about their use of cannabis-based products.
There were 11,006 respondents total, and their cannabis use went up from 6.3% in 2014 to 18.4% in 2019, with most users in U.S. states where cannabis use is legal.
"Most users (74% in 2014; 62% in 2019) reported that cannabis was effective for relief of arthritis symptoms." It seems they tried cannabis because their pain management needs were not be adequately addressed by other therapies.
The report is here.