Altered sleep in axial spondyloarthritis and psoriatic arthritis: Post hoc comparative study based on a sleep-specific question from the ASAS health index.

BACKGROUND AND AIMS: Sleep problems are common in spondyloarthritis (SpA), but the factors associated with them are only partially known. In this study, responses to item #16 from the Assessment of SpondyloArthritis international Society-Health Index (ASAS HI) that explores the sleep category according to the International Classification of Functioning, Disability and Health (ICF) were compared between psoriatic arthritis (PsA) and axial SpA (axSpA).

METHODS

Post hoc analysis of a multicentre cross-sectional study included a total of 201 consecutive patients. The prevalence, correlations, and disease factors associated with a positive response to item #16 were analyzed in both SpA populations.

RESULTS

Forty-eight/111 (43.2%) patients with axSpA and 42/90 (46.7%) with PsA reported sleep problems. There was a moderate-high correlation between item #16 and the ASAS HI sum score in both populations (r≥.59). In axSpA, poor sleep was associated with disease activity (OR 8.45, p<.001), biological therapy use (OR .24, p<.05) and CRP levels (OR .16, p<.05). In PsA, disturbed sleep was independently associated with disease activity showing a dose-response effect (OR 1.16, p<.001). Taking both populations together, disease severity (OR 6.33, p<.001) and axSpA (OR .50, p<.05) were independently associated with a positive response to item #16. Correlations between the different components of the ASAS HI and item #16 were markedly different in both populations.

CONCLUSIONS

A positive response to item #16 was common in both SpA phenotypes. However, the link between inflammatory burden and disturbed sleep was higher in axSpA than in PsA.