Effect of lung function on the apnea-hypopnea index in patients with overlap syndrome: a multicenter cross-sectional study.

Lung function was associated with the AHI in patients with OVS. The lower FEV1 may play some protective role in the severity of AHI in OVS patients. Trial registry ClinicalTrials.gov , No.: NCT03182309, URL: www.clinicaltrials.gov .