Study of the Psychometric Properties and a Measure of Utility Determinants ( the SF- 6D) in Patients With Early Inflammatory Low Back Pain

Study Overview
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Brief Summary
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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.

Conditions
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Spondylarthritis

Participation Criteria
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Eligibility Criteria
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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) .

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Level of utility measured by the SF-6D | The SF-6D derives from 11 questions of the SF36 using the algorithm of Brazier et al which then provides a unique score. It has 6 dimensions: Physical Function, Role Limitation, Social Function, Pain, Mental Health and Vitality with 4 to 6 levels of responses depending on the dimension. SF-6D thus makes it possible to describe 18,000 health conditions. The utility score obtained with SF-6D varies between 0.29 and 1. | baseline (0 months) | 
| Level of utility measured by the SF-6D | The SF-6D derives from 11 questions of the SF36 using the algorithm of Brazier et al which then provides a unique score. It has 6 dimensions: Physical Function, Role Limitation, Social Function, Pain, Mental Health and Vitality with 4 to 6 levels of responses depending on the dimension. SF-6D thus makes it possible to describe 18,000 health conditions. The utility score obtained with SF-6D varies between 0.29 and 1. | 6 months | 
| Level of utility measured by the SF-6D | The SF-6D derives from 11 questions of the SF36 using the algorithm of Brazier et al which then provides a unique score. It has 6 dimensions: Physical Function, Role Limitation, Social Function, Pain, Mental Health and Vitality with 4 to 6 levels of responses depending on the dimension. SF-6D thus makes it possible to describe 18,000 health conditions. The utility score obtained with SF-6D varies between 0.29 and 1. | 12 months |