CHICAGO — Renal stones are more prevalent in ankylosing spondylitis patients than in those with rheumatoid arthritis, according to the results of a preliminary study presented at the combined annual meeting of the Central Society for Clinical Research and the Midwestern section of the American Federation for Medical Research.
The investigation, led by Susan A. Leonard, M.D., of the University of Minnesota, Minneapolis, was the first to describe an association between nephrolithiasis and spondyloarthritis since a Croatian study that was published more than 30 years ago (Reumatizam 1973;20:106–10), according to Hollis E. Krug, M.D., who presented the latest data in a poster session at the meeting.
In their retrospective cohort study of 44 patients with spondyloarthritis and 51 controls with RA undergoing treatment at the Minneapolis Veterans Affairs Medical Center, the Minnesota-based researchers found a statistically significant greater prevalence of renal calculi in patients with ankylosing spondylitis compared with those with RA (38.6% versus 15.7%).
“There didn't seem to be a higher rate of coexistent disease in spondyloarthritis patients that could increase the risk for renal stones,” Dr. Krug said. However, medication use at diagnosis of nephrolithiasis was not documented in the patients' charts, and that may have played a role in formation of kidney stones, she told this newspaper.
The Minneapolis group plans to study more patients in an attempt to explain the reason for this association.