Improvement in HRQOL measured by SF-6D was associated with younger age, higher education, low Bath Ankylosing Spondylitis (BAS) Activity Index (BASDAI), high BAS Patient Global Score and high C-reactive protein; improvement in SF-36 PCS was associated with younger age, higher education, low BASDAI and no use of biological treatment at baseline. Here, CRP is linked to ankylosing spondylitis.