The role of orexin in fatigue and sleep quality in patients with primary Sjögren’s syndrome

Background Sleep disorders and fatigue are prevalent symptoms affecting primary Sjögren’s syndrome (pSS) patients. This study aimed to assess the sleep quality of pSS patients as well as its relationship to fatigue and orexin level. Methods This is a cross-sectional study evaluating fatigue in pSS using the Fatigue Severity Scale (FSS). Sleep quality was evaluated using the Pittsburg Sleep Quality Index (PSQI). The European Alliance of Associations for Rheumatology (EULAR) Sjögren’s Syndrome Disease Activity Index (ESSDAI) and EULAR Sjögren’s Syndrome Patient-Reported Index (ESSPRI) were calculated. Results Forty-one patients met the sample criteria and were involved in the final report. They were all females, with a mean (± SD) age and median disease duration of 40.87 ± 10.84 and 36 (6–180) months, respectively. The mean ESSDAI was 0.92 ± 1.3, while the mean ESSPRI was 5.8 ± 2.13. Based on the FSS, 32 (78.04%) patients had a positive test with a mean score of 5.07 ± 1.54. The total PSQI score showed that 60.97% had poor sleep, and the orexin level was lower in patients with pSS than in healthy controls. There was no correlation between orexin level and the presence of fatigue nor the PSQI score. Conclusion In conclusion, serum orexin levels were lower in patients with pSS than healthy controls, It could be related to impairments in sleep and fatigue in patients with pSS.