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Abstract
Background Health-related quality of life (HRQoL) is significantly reduced in patients (pts) with ankylosing spondylitis. A limited number of studies reported a lower HRQoL in pts with axial Spondyloarthritis (axSpA). However, it is unknown how HRQoL evolves over time in pts with early axSpA and pts referred because of suspicion of axSpA.
Objectives To describe HRQoL at baseline and after one year in pts with axSpA and other forms of chronic back pain in the SpondyloArthritis Caught Early (SPACE)-cohort.
Methods The SPACE study is a prospective cohort study among pts with chronic back pain (≥3 months, ≤2 years, onset <45 years) recruited from 5 centres in the Netherlands, Norway, and Italy. HRQoL is measured at baseline and 1 year by the 36-item Short-Form (SF-36). After recoding and recalibration, raw scale scores are obtained and converted in scale scores with a range of 0 (worst) to 100 (best). The scale scores are weighted according to sex and age matched scores for each country and adjusted for the general population mean of 50, SD of 10. Subsequently, the scale scores are used to calculate the physical (PCS) and mental component summary (MCS) scores. The minimally clinically important difference (MCID) is defined as a minimum of 3 points.
Results Data of the Netherlands and Italy are presented. The SF-36 was completed by 91 pts at both baseline and 1 year. Pts were classified according to the ASAS axSpA classification criteria: no axSpA (i.e. no axSpA features, n=13), possible axSpA (i.e. not fulfilling the criteria but ≥1 axSpA features; n=27), clinical arm of the ASAS axSpA criteria (n=31), and imaging arm of the ASAS axSpA criteria (n=20). Mean PCS was decreased in all pts groups at both time points compared to general population (50±10), with the lowest scores in the possible axSpA group (23.6 at baseline, 29.0 at 1 year, table 1). At 1 year, mean PCS increased in all pts groups. An improvement in PCS ≥ MCID was observed in 52 pts (51.1%, 8 no axSpA, 14 possible axSpA, 18 axSpA clinical arm, 12 axSpA imaging arm) after 1 year. Twenty-three pts (25.3%, 5 no axSpA, 7 possible axSpA, 6 axSpA clinical arm, 5 axSpA imaging arm) showed a decrease in PCS ≥ MCID after 1 year. Mean MCS scores at both time points were comparable for each axSpA group and were only slightly decreased in comparison to the general population. In general, MCS scores increased somewhat after 1 year. After 1 year 40 pts (44.0%, 4 no axSpA, 14 possible axSpA, 15 axSpA clinical arm, 7 axSpA imaging arm) showed an increase in MCS score and 26 pts (28.6%, 4 no axSpA, 7 possible axSpA, 9 axSpA clinical arm, 6 axSpA imaging arm) a decrease in MCS score ≥ MCID. The number of pts was insufficient to compare the participating countries.
Conclusions HRQoL is mainly reduced due to lower PCS scores. Compared to the general population, the PCS score is substantially decreased to 23-35 points in pts with axSpA or other forms of chronic back pain whereas the MCS score approximates the general population mean. Over 1 year, in our cohort the PCS improved slightly but remained significantly impaired.
Disclosure of Interest None declared