Determinants of sleep impairment in psoriatic arthritis: An observational study with 396 patients from 14 countries.

Objective: Sleep quality is diminished in patients with psoriatic arthritis (PsA) and close to 40% of PsA patients consider sleep difficulties a priority domain. This work analyzes determinants of impaired sleep in patients with PsA.

Methods: This was a cross-sectional analysis of an observational study (ReFlap, NCT NCT03119805), which included adult patients with definite PsA with≥2 years disease duration from 14 countries. Sleep was assessed using the patient self-reported evaluation of sleep on a 0-10 numerical scale, included in the Psoriatic Arthritis Impact of Disease questionnaire (PSAID-12). A score≥4 was considered as sleep impairment. Demographic and clinical variables associated to sleep impairment were assessed through univariate analysis and Poisson regression modeling leading to prevalence ratio (PR) [95% confidence interval].

Results: A total of 396 patients were analyzed: mean age 51.9±12.6 years, 51% were females, 59.7% were receiving biologic therapy, 53.3% had 1-5% of body surface area affected by psoriasis; 23.7% were in remission and 36.9% in low disease activity according to the Disease Activity in Psoriatic Arthritis (DAPSA) score. Median (25th-75th) patient's self-evaluation of sleep difficulties was 2 (0-6), 157 (39.6%) had sleep impairment. In the Poisson regression model, self-reported levels of anxiety (PR: 1.05 [1.02-1.08], P=0.003) and pain (PR: 1.06 [1.04-1.09], P<0.001) were independently associated to sleep impairment.

Conclusions: In this multicentric study, sleep impairment was present in 40% of PsA patients; pain and anxiety were associated to sleep impairment whereas inflammation was not. Impact on sleep appears multifactorial in PsA.