In the absence of an ideal objective measure for assessing ankylosing spondylitis (AS), self-administered measures of disease activity (the Bath Ankylosing Spondylitis Disease Activity Index, BASDAI) and function (the Bath Ankylosing Spondylitis Functional Index, BASFI) have been developed, in addition to an objective measure of spinal mobility (the Bath Ankylosing Spondylitis Metrology Index, BASMI). However, a more global assessment is also desirable. We report on the design and validation of a global measure (the Bath Ankylosing Spondylitis Patient Global Score, BAS-G) which reflects the effect of AS on the patient's well-being. A pilot study was performed to select the most appropriate wording for BAS-G. Using 392 patients with AS, BAS-G's construct and predictive validity and test-retest reliability were assessed. Correlations between BAS-G and BASDAI/BASFI were calculated, and multiple regression was used to examine the significant correlates. The distribution of the responses covered the whole scale. As predicted, BAS-G correlated best with BASDAI (r=0.73), followed by BASFI (r=0.54). The best fitting regression equation included these scales as well as patients' gender and current age. One week and 6 month scores were significantly different (P<0.001). Construct validity was good: BAS-G correlated more strongly with each component of BASDAI and BASFI than with BASMI or with gender. Predictive validity was satisfactory: there was an improvement (mean=29%) in in-patient BAS-G scores over a 2 week treatment period (P<0.001). Test-retest reliability was excellent (1 week r=0.84, 6 months r=0.93). BAS-G correlates well with both BASDAI and BASFI, suggesting that disease activity and functional ability play a major role in patients' well-being, whereas metrology does not. The score is sensitive to change, reliable, and meets face, predictive and construct validity criteria.

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(1) spondylodiscitis occurs in approximately 8% of patients with AS; (2) these patients have early onset of disease; (3) multiple-level lesions in the spine are not uncommon among those with spondylodiscitis; (4) lesions are usually asymptomatic.

The objective was to compare the Bath Ankylosing Spondylitis Metrology Index (BASMI) with radiology as a measure of disease outcome. Fifty-three patients, covering the entire spectrum of disease severity, were blindly and independently assessed using the BASMI (total of five standardized measurements, scoring range 0-10) and a radiology score of the four main spinal areas affected by ankylosing spondylitis (AS). BASMI correlates positively with the total radiology score (r = 0.74), while the individual BASMI scores for cervical rotation (r = 0.59), wall to tragus (r = 0.61), lumbar side flexion (r = 0.56), lumbar flexion (r = 0.68) and intermalleolar distance (r = 0.50) correlate positively with their respective radiology scores. BASMI and radiology do not relate well to each other as BASMI takes account of normal physical limitation and soft tissue involvement. In addition, although radiology scores are termed a 'gold standard', they are unreliable. Therefore, BASMI may be judged to be more important in assessing AS and become a 'gold standard' itself.

About 1 in 200 patients with AS undergo cervical spine surgery. The surgery is often successful and complications are usually minor. Neck pain is often better after surgery and any remaining neck symptoms do not significantly affect the patient's sleep or functional activities. In this retrospective study, the long term outcome of cervical spine surgery in patients with AS appears to be good.