Obstructive Sleep Apnea in Psoriatic Arthritis: Clinical Characteristics and Comorbidities

Background: Obstructive sleep apnea (OSA) is increasingly recognized in chronic inflammatory diseases, yet its prevalence and clinical correlates in psoriatic arthritis (PsA) remain poorly characterized. Objective: The objective of this study was to evaluate OSA prevalence and its relationship with disease activity, functional impairment, and comorbidities in PsA patients. Methods: A cross-sectional analysis of 247 consecutive PsA patients was conducted. OSA diagnosis was determined through medical record review. Disease activity was assessed using cDAPSA and ASDAS-CRP. Functional disability was measured using HAQ-DI and BASFI. Sleep quality (PSQI) and psychological symptoms (HADS) were evaluated. Inflammatory markers included CRP, IL-6, and TNF-α. Multivariable logistic regression identified independent predictors of OSA. Results: OSA prevalence was found to be 8.9% (22/247). OSA+ patients had significantly higher median age (58.0 vs. 54.0 years, p = 0.02), tender joint count (2.0 vs. 1.0, p = 0.002), functional disability (1.1 vs. 0.3, p = 0.001), fatigue (30.5 vs. 38.0, p = 0.04), anxiety (7.5 vs. 5.0, p = 0.03), depression (7.0 vs. 3.0, p = 0.004), and worse sleep quality (11.5 vs. 7.0, p = 0.001). Notably, no significant differences in inflammatory markers (CRP, swollen joints) were found between groups despite substantially higher pain burden in OSA+ patients. Female sex and greater tender joint count emerged as independent predictors of OSA. Conclusions: OSA occurs in ~9% of unselected PsA patients and is independently associated with functional disability, psychological distress, and elevated tender joint counts despite comparable inflammatory markers. This dissociation suggests that OSA drives pain amplification through non-inflammatory mechanisms. These findings support the use of systematic OSA screening in PsA patients with pain or disability disproportionate to inflammatory burden, particularly in those with psychological comorbidities.