Sleep features in Lymphangioleiomyomatosis and their relationship with disease severity: a pilot study

Lymphangioleiomyomatosis (LAM) is a rare pulmonary disease characterized by progressive airflow limitation. We conducted a pilot trial to investigate the incidence of sleep disorders, sleep quality and their relationship with disease severity. We performed pulmonary function tests, blood gas analysis, overnight 12-channels polysomnography and clinical assessments in 15 consecutive LAM patients. For statistics, p values < 0.05 were considered significant. Sleep efficiency (SE) was inversely correlated with RV/TLC (p = 0.035) and positively with daytime SpO2 (p = 0.010) and PaO2 (p = 0.011). Three cases had obstructive sleep apnea (OSA); seven patients (46.7%) showed a REMOSA. AHI_REM was correlated with FEV1% (r = 0.75, p = 0.003), TLC% (r = 0.57, p = 0.026), RV% (r = 0.8, p=<0.0001) and RV/TLC (r = 0.77, p = 0.001). No correlations were observed between anxiety/depression and SE, CAP rate, pulmonary function test variables and AHI_REM (p > 0.05). four subjects had nocturnal hypoxia (T90 ≥ 1% of TST) showing lower values of DLCO%, daytime SpO2%, PaO2, FEV1% and a higher value of VR/TLC comparing with the subgroup with normal T90 (p < 0.05). This pilot study shows that sleep alterations could be frequent in LAM and associated to disease severity. Nocturnal hypoxemia and SE were related to lung function impairment. A dysregulation of sleep seems to involve exclusively REM phase, while NREM appears to be preserved. This phenomenon might be linked to the pathophysiology of disease: our study, even with the limits of the small sample size, showed that the presence of REMOSA is related to the disease severity, in particular to the degree of airflow limitation and hyperinflation. More studies are needed to assess this topic.