COPD–OSA overlap in hospitalized GOLD group E patients: Detection yield, nocturnal hypoxemia, and AHI/REI correlates

Background COPD–OSA overlap is associated with adverse outcomes, yet data in hospitalized high-risk COPD patients remain limited. We assessed the detection yield of OSA using a STOP-Bang–guided pathway and characterized respiratory-polygraphy findings and AHI correlates in GOLD group E inpatients. Methods In this hospital-based observational study at Bach Mai Hospital, Hanoi, Vietnam, 5,327 COPD patients were evaluated; 1,736 were hospitalized due to COPD exacerbation and classified as GOLD group E. All inpatients were screened using STOP-Bang. Patients with STOP-Bang ≥3 were eligible for respiratory polygraphy. OSA was defined as AHI/REI ≥5 events/hour. Associations were examined using Spearman’s rank correlation and linear regression with ln (AHI/REI + 1), adjusted for age, sex, BMI, and PaCO₂. Results Of 1,736 hospitalized COPD patients, 123 underwent respiratory olygraphy and 103 had confirmed OSA, corresponding to a STOP-Bang–guided detection yield of 5.9% rather than an unselected prevalence estimate. OSA severity was mild in 44.7%, moderate in 28.2%, and severe in 27.2%. Median AHI/REI was 16.1 events/h, ODI 19.0 events/h, minimum SpO₂ 80.0%, and T90 47.1 min. AHI/REI correlated weakly with age and BMI. FEV₁% predicted showed no significant association with ln (AHI/REI + 1) after adjustment. Conclusions STOP-Bang–guided respiratory polygraphy identified clinically relevant OSA and substantial nocturnal desaturation in hospitalized GOLD group E COPD patients. The 5.9% estimate represents detection yield, not OSA prevalence in unselected COPD populations.