CRP and ankylosing spondylitis: Furthermore, elevated time-averaged CRP levels (>6 mg/L) relative to levels ≤6 mg/L were significantly and independently associated with the formation of new syndesmophytes and radiographic progression (defined as an increase of two or more modified Stoke Ankylosing Spondylitis Spine Score units after 2 years) in the spine in AS [13].