The general main objective of our study is to investigate the psychometric properties, the levels and determinants of the extent of SF- 6D utility in patients followed for recent back pain inflammatory disease.

The specific objectives are :

• Study the feasibility of the tool considering missing data, distribution, construct validity, reproducibility, sensitivity to change or clinically different groups (discriminative ability) the extent of SF -6D utility .
• Study the impact of socio-demographic characteristics, disease characteristics and quality of life, comorbidities at baseline on the measurement of utility and sensitivity to change.

Inclusion Criteria:

• The patient should be given free and informed consent and signed the consent

  • The patient must be affiliated or beneficiary of a health insurance plan
  • patients aged 18 years and under 50
  • inflammatory back pain (buttocks , lumbar or thoracic spine )
  • fulfilling the criteria of Calin or Berlin (30,31)
  • duration of symptoms than three months and less than three years
  • symptoms suggestive of spondyloarthritis as assessed by the local investigator ( score≥5 on a numerical scale from 0 to 10 where 0 = no evocative and 10 = very suggestive of spondyloarthritis ) .

Exclusion Criteria:

• Another clearly defined spinal disease (eg discarthrose )

  • history of treatment with biotherapy
  • taking glucocorticoids allowed only in low dose of less than 10mg of prednisone daily and stable for at least four weeks before inclusion
  • Current or history anomalies that could interfere with the validity of informed consent and / or prevent a patient's optimal adhesion to the cohort (eg , alcoholism , mental illness) .

708 patients with early inflammatory low back pain included in the French cohort DESIR