CRP and spondyloarthropathy: Studies have found that GDM is more effective for patients with nonimpact spondyloarthritis who have high C-reactive protein (CRP) levels and/or positive MRI results.[31] In a 16-week, randomized, double-blind, placebo-controlled study,[32] 197 patients were randomized to receive either GDM (n = 97) or placebo (n = 100).