Towards a multidimensional patient reported outcome measures assessment: development and validation of a questionnaire for patients with ankylosing spondylitis/spondyloarthritis.

OBJECTIVE

To assess the validity, reliability and responsiveness to change of a patient self-reported questionnaire that can assess construct outcome measures of patients with ankylosing spondylitis (AS)/spondyloarthritis.

METHODS

The questionnaire was developed by integrating information obtained from patients suffering from AS/spondyloarthritis based on the Rasch model. The questionnaire includes assessment of functional disability, quality of life, VAS for spinal pain, joint pain, global status, fatigue, duration of morning stiffness, review of the systems, falls and cardiovascular risks, self-helplessness as well as self-reported joint and soft tissue pain. The questionnaire was completed by 267 consecutive patients with AS (124) and spondyloarthritis (143).

RESULTS

The PROMs questionnaire was reliable as demonstrated by a high-standardized alpha. The questionnaire items correlated significantly (p<0.01) with clinical parameters of disease activity. Patient reported tender joints and enthesitis scores correlated significantly with the physician's scores (correlation coefficient 0.848 and 0.821 respectively). Changes in functional disability, quality of life as well as self-helplessness scores showed significant (p<0.01) variation with diseases activity status. The PROMs questionnaire showed also a high degree of comprehensibility (9.3).

CONCLUSIONS

The developed PROMs questionnaire is a reliable and valid instrument for assessment of patients suffering from AS and spondyloarthritis. Being short, rapid and comprehensive, this adds more to its applicability. The data support the value of completion of the simple two pages patient questionnaire, which provides a quantitative written documented record by the patient, at each visit to the rheumatologist.