Following previous work, we investigated four continuous measures of disease activity as the primary outcomes, including the disease activity score 28 with C-reactive protein (DAS28-CRP) for psoriatic arthritis and rheumatoid arthritis, the ankylosing spondylitis disease activity score with C-reactive protein (ASDAS-CRP), and the psoriasis area and severity index (PASI) score [10]. Here, CRP is linked to ankylosing spondylitis.