Sleep quality in patients with primary Sjögren's syndrome

Objective To assess the sleep quality in primary Sjögren’s syndrome (pSS) patients and evaluate its relationship with the disease, quality of life and mood disorders. Methods The sleep quality of 29 pSS women and 29 matched controls was assessed by the Pittsburgh Sleep Quality Index (PSQI). Seven domains are grouped according to three factors: F1 perceived sleep quality (subjective sleep quality, sleep latency, use of sleeping medication), F2 sleep efficiency (sleep duration, habitual sleep efficiency) and F3 daily disturbances (sleep disturbances, daytime dysfunction). These domains are scored as a single factor of global sleep quality. The Short Form Health Survey (SF-36), Functional Assessment of Chronic Illness Therapy (FACIT) fatigue scale and Hospital Anxiety and Depression Scale (HADS) were also administered. Disease activity and damage were evaluated with the EULAR Sjögren’s syndrome disease activity index (ESSDAI), the Sjögren’s Syndrome Disease Activity and Damage Indexes (SSDAI, SSDDI). Results The mean PSQI global score had higher pathological values (8.6±4.6) compared with controls (5.6±2.2) (p=0.002). F1 and F3 were significantly worse in cases (p=0.01, p=0.009). A negative correlation was found between SF-36 subscales and the global PSQI, F2 and F3. The anxiety HADS correlated with F2 and F3, while depression only with F3. No correlation with FACIT and disease indexes emerged. Conclusion Using PSQI, an impaired sleep quality was demonstrated in pSS patients, especially with perceived quality and the daily disturbances. It is associated with a reduced quality of life but not with disease-related variables.