Patients with well-established ankylosing spondylitis show limited deterioration in a ten-year prospective cohort study.

This study aims to describe the deterioration of well-established ankylosing spondylitis (AS) over a 10-year period. Patients with well-established AS under secondary care review were assessed at baseline and re-assessed after a 10-year period. Data on patient characteristics, spinal mobility and self-reported health status (AS Quality of Life, Bath AS Disease Activity Index, EuroQoL, Revised Leeds Disability Questionnaire and Short Form-12) were compared between the two time points. One hundred fifty-nine patients took part in the initial assessment. After 10 years, 69/117 patients still under secondary care follow-up attended a second assessment. At the second assessment, this cohort was predominately male (92.8 %), mean age of 48.7 years (SD 9.7) and mean disease and symptom duration of 14.9 (SD 9.0) and 21.9 years (SD 13.3), respectively. Amongst the physical and patient-reported measures, only tragus to wall (p < 0.001), cervical rotation (p = 0.001) and disability (p = 0.02) had significantly deteriorated over time. The percentage of patients who had withdrawn from the workforce before normal retirement age increased from 37 to 53 % over the 10-year period. Many of the measures used in the assessment of AS do not generally deteriorate over time in those with well-established disease. This suggests that deterioration may plateau in established disease. However, AS has a long-term social impact with levels of employment in this cohort 30 % lower than the general population. Interventions directed at preventing deterioration may be more effective earlier in their disease course, before this plateau is reached.