Evaluation of sleep related breathing disorders and obstructive sleep apnea in patients with interstitial lung disease

Patients with ILD are at risk for sleep disorders due to respiratory abnormalities and adverse effects of treatment.We aimed to determine the relationship between quality of sleep,sleep disordered breathing and incidence of obstructive sleep apnea in these patients. Fifty two patients with ILD were enrolled in study. Pittsburgh Sleep Quality Index(PSQI) and Epworth Sleepiness Score(ESS) were applied. All patients underwent spirometry and COdiffusion test. Polysomnography was performed to 27 patients who had an ESS >=10.Subjective parameters of sleepiness and sleep quality compered with PSG mesurements. Patients were classified according to daytime sleepiness. Demographic characteristics, body mass index, immunosuppressive medication, spirometry and diffusion measurements, the sub-components of PSQI and global score didn’t differ between groups.Subjective sleep quality was poor in 44% of patients. PSQI global score and sub-components weren’t correlated with AHI, stage 1 latency, sleep efficiency and nocturnal desaturation. We found increased stage 1 sleep and decreased stage 2-3 and REM sleep.Nocturnal hypoxemia was determined related with severity of restriction, arousals and sleep efficiency.Nineteen(70%) of subjects were diagnosed with OSAS. AHI was negatively correlated with percentage of FEV1-FVC and sleep efficiency and was evident during REM sleep and supine position. Although patients with ILD don’t have daytime hypoxemia; nocturnal hypoxemia estimated by severity of restriction can contribute to apnea- hypopnea episodes. Therefore ILD patients must be evaluated for daytime sleepiness, sleep quality and inspected for sleep-related breathing disorders.