Relationship of chronic fatigue with sleepiness and melatonin level in primary sjogren's syndrome patients

Fatigue is one of the most frequent manifestations of sjogren's syndrome. Pain, sleep disorders, learned helplessness and neuroendocrine and autonomic dysfunction are suggested factors that can effect the fatigue. The aim of the present study is to evaluate relationship between chronic fatigue, sleep disorders, quality of life and melatonin level. One hundred and sixteen PSS patients followed in Akdeniz University Internal Medicine Rheumatology Department and twenty seven controls were included between period of April 2014 and April 2015. All patient completed epworth sleepiness scale, fatigue severity scale and SF-36 which is a measure of quality of life. Serum melatonin levels were investi¬gated in all participants. While 79.5% of patients with daytime sleepiness had fatigue, only 45.8% of patients without daytime sleepiness had fatigue (p<0,05). Day time sleepiness and fatigue had negative effect on quality of life (SF-36) (p<0,05). The median melatonin level of patients was 254 ng/L (IQR 197-491) while it was 429 ng/L (IQR 268-774) in control group (p<0.05). Median melatonin level of patients without daytime sleepiness was 270 ng/L (IQR202-603), on the other hand melatonin level of patients with daytime sleepiness was 234 ng/L (IQR 191-363) (p>0.05). In patients with fatigue the median value of melatonin was 239 ng/L (IQR 189-460), in patients without fatigue it was 266 ng/L (IQR 219-552). Fatigue is more prominent in patients with daytime sleepiness and daytime sleepiness and fatigue have negative effect on quality of life. Median melatonin level is higher in patients compared to control group but melatonin level is not related to fatigue or day time sleepiness.