Sleep-Disordered Breathing in Patients with Chronic Obstructive Pulmonary Disease: Prevalence and Outcomes
José M. Marı́n, Joan B. Soriano, Marta Marín‐Oto, Juan P. de‐Torres, Luis Seijó, Carlos Cabrera López, Ingrid Solanes, Cristina Martínez González, Núria Toledo-Pons, Nuria Feu, Carlos Antonio Amado Diago, Laura Vigil, Bartolomé R. Celli, Ciro Casanova
Abstract
Abstract Rationale The prevalence of obstructive sleep apnea (OSA) or nocturnal hypoxemia without OSA (i.e., isolated nocturnal hypoxemia [iNH]) and its impact on the natural history of chronic obstructive pulmonary disease (COPD) are unclear. Objective We determined the prevalences of OSA and iNH in patients with COPD and their contribution to all-cause mortality and COPD exacerbations. Methods At baseline, we performed home sleep apnea testing in the CHAIN (COPD History Assessment in Spain) study cohort. OSA was defined by an apnea–hypopnea index of ⩾15 events per hour, and iNH was defined by an oxygen saturation as measured by pulse oximetry <90% for >30% of the nocturnal recording time. During an observation time of 6.5 years, we evaluated the association of OSA or iNH with all-cause mortality using multivariable Cox regression models and with COPD exacerbations using negative binomial models. Results Among 428 patients with COPD, OSA and nocturnal hypoxemia were ruled out in 41%, whereas 27% had iNH and 32% had OSA (i.e., COPD/OSA “overlap syndrome” [OVS]). OVS was independently associated with obesity as defined by a body mass index ⩾30 kg/m2 and with severe COPD exacerbations (P < 0.01), whereas iNH was associated with lower forced expiratory volume in 1 second and lower resting arterial oxygen saturation. Compared with patients with COPD without OSA or iNH, those with untreated OVS had greater risks of mortality (hazard ratio, 1.74; 95% confidence interval, 1.03–2.94) and COPD exacerbations (incidence rate ratio, 1.44; 95% confidence interval, 1.05–2.03). Conclusions OSA and iNH are frequent in patients with COPD, and the prevalences decrease or increase, respectively, with disease severity. Patients with COPD with untreated OVS but not with iNH had a greater risk of all-cause mortality and COPD exacerbations.