Pain, xerostomia, and younger age are major determinants of fatigue in Korean patients with primary Sjögren's syndrome: a cohort study.
OBJECTIVE
Fatigue is a common clinical manifestation in patients with primary Sjögren's syndrome (pSS). The aims of this study were to investigate the association between fatigue severity and other clinical characteristics in pSS patients and to determine the factors contributing to fatigue.


METHODS
We analysed 257 participants from the Korean Initiative of pSS (KISS), a prospective pSS cohort. Fatigue was assessed according to the fatigue domain of the European League Against Rheumatism (EULAR) Sjögren's Syndrome Patient-Reported Index (ESSPRI). Health-related quality of life (HRQoL) was evaluated using the EuroQol-5 dimensions (EQ-5D) questionnaire. Multiple linear regression analysis was used to estimate the effect of each variable on fatigue severity.


RESULTS
The median total ESSPRI score was 5 [interquartile range (IQR) 4-6]. Thirty-four per cent of patients reported a fatigue score > 5. Younger and premenopausal patients presented with more fatigue (p = 0.013 and p < 0.001, respectively). Higher Xerostomia Inventory (XI) scale (p < 0.001) and Ocular Surface Dryness Index (OSDI) (p < 0.001) scores were observed in patients with a fatigue score > 5. Pain, xerostomia, and age were determined to be significantly associated with fatigue severity after adjusting for depression/anxiety, OSDI score, and the presence of fibromyalgia using a multivariate general linear model. The ESSPRI fatigue score was correlated with the EQ-5D by time trade-off (TTO) values and visual analogue scale (VAS) scores.


CONCLUSIONS
In Korean patients with pSS, younger age, xerostomia, and pain were correlated significantly with fatigue, and fatigue was associated with HRQoL.
a Division of Rheumatology, Department of Internal Medicine, Seoul St Mary's Hospital, College of Medicine , The Catholic University of Korea , Seoul , South Korea.
J H
JH
Koh
a Division of Rheumatology, Department of Internal Medicine, Seoul St Mary's Hospital, College of Medicine , The Catholic University of Korea , Seoul , South Korea.
S K
SK
Kwok
a Division of Rheumatology, Department of Internal Medicine, Seoul St Mary's Hospital, College of Medicine , The Catholic University of Korea , Seoul , South Korea.
J
J
Lee
b Division of Rheumatology, Department of Internal Medicine , Keimyung University Dongsan Medical Centre , Daegu , South Korea.
C N
CN
Son
b Division of Rheumatology, Department of Internal Medicine , Keimyung University Dongsan Medical Centre , Daegu , South Korea.
J-M
JM
Kim
c Division of Rheumatology, Department of Internal Medicine , Gyeongsang National University School of Medicine , Jinju , South Korea.
H O
HO
Kim
d Division of Rheumatology, Department of Internal Medicine , Catholic University of Daegu School of Medicine , Daegu , South Korea.
S H
SH
Park
e Department of Rheumatology , Hanyang University Hospital for Rheumatic Diseases , Seoul , South Korea.
Y K
YK
Sung
d Division of Rheumatology, Department of Internal Medicine , Catholic University of Daegu School of Medicine , Daegu , South Korea.
J Y
JY
Choe
f Division of Rheumatology, Department of Internal Medicine , Chonnam National University School of Medicine , Gwangju , South Korea.
S S
SS
Lee
a Division of Rheumatology, Department of Internal Medicine, Seoul St Mary's Hospital, College of Medicine , The Catholic University of Korea , Seoul , South Korea.
S H
SH
Park
D000367:Age Factors; D015331:Cohort Studies; D005221:Fatigue / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology; D011788:Quality of Life; D056910:Republic of Korea / Q000453:epidemiology; D012859:Sjogren's Syndrome / Q000150:complications* / Q000453:epidemiology; D014987:Xerostomia / Q000209:etiology