Patients with primary Sjögren's syndrome (pSS) have higher fatigue levels and also suffer from excessive day time sleepiness. The underlying mechanisms for this are not fully understood. Knowing that these patients have higher salivary surface tension, we postulated that sleep disordered breathing (SDB) would be more common and would be a contributor to these symptoms amongst pSS patients. We investigated the prevalence of SDB in pSS patients and its relationship to their symptoms of fatigue and excessive daytime sleepiness.
This was an observational study of 28 pSS patients (mean±SEM age, 58.7±1.9) and 18 healthy subjects (mean±SEM age, 55.8±3.4) matched for age, sex, and BMI. All the participants underwent an overnight polysomnography. The two groups were compared for fatigue, sleepiness, anxiety, and depression scores, and for the frequency of obstructive apneas and hypopneas during sleep. Correlation analyses were used to explore relationships between sleep study variables and excess sleepiness and fatigue.
Fatigue, sleepiness, anxiety and depression symptoms, and sleep onset latency were significantly greater in pSS patients than controls. pSS patients had twice the frequency of obstructive apneas and hypopneas compared with control subjects (median[IQR],18.6/h [10.4-40.1] vs. 9.9/h [6.5-23.4]; p=0.032) and OSA defined as an apnea-hypopnea index >15 events/h of sleep was more prevalent amongst pSS patients than controls (64% vs. 28%; p=0.033). While no significant correlations were found between parameters of sleep disordered breathing and sleepiness scores or fatigue scores in the pSS group, CPAP treatment in a small subset of the pSS who were more severely affected by OSA suggested significant symptomatic benefit.
OSA appears to be increased in pSS and may be a useful therapeutic target to improve the quality of life of these patients.