Spondyloarthropathy: an independent risk factor for kidney stones.

Purpose: To better stratify risk and to verify previous prevalence reports, we conducted a retrospective cohort study comparing the lifetime incidence of nephrolithiasis in patients with spondyloarthropathies (SpA) and rheumatoid arthritis (RA). Patients and Methods: Patients with SpA or rheumatoid factor-positive RA were identified from the rheumatology clinics of two Veterans Affairs hospitals and the University of Minnesota. Among them, 168 were confirmed to meet the American College of Rheumatology criteria and gave informed consent to participation. They were sent a survey regarding their rheumatologic diagnosis, coexistent conditions, medications, and history of kidney stones. Of the total, 143 patients responded and met the criteria for analysis. Rheumatoid arthritis patients were age and sex matched with SpA patients as controls. Results: Populations were similar in all categories except that RA patients were more likely to have used prednisone (P < 0.001), bisphosphonates (P < 0.001), and calcium...