Background: Chronic obstructive pulmonary disease (COPD), obstructive sleep apnea (OSA), and periodic limb movements of sleep (PLMS) frequently co-occur and may exacerbate nocturnal hypoxemia. Still, their combined effects are not well defined. Objectives: To examine the independent and interactive effects of COPD, OSA, and PLMS on nocturnal oxygen desaturation. Design: Cross-sectional analysis of a sleep study cohort. Methods: We analyzed 711 participants (mean age 57.2 ± 17.9 years; 44.4% male), including 48 with COPD. Time with oxygen saturation ⩽88% (ST) and mean SpO 2 were compared across COPD and OSA/PLMS subgroups. Multivariable regression tested the independent and interaction effects of COPD, OSA, PLMS, age, and sex. Results: Participants with COPD had lower mean SpO 2 and longer ST than non-COPD participants ( p < 0.005). ST was greatest in those with both OSA and PLMS, particularly in COPD. COPD (+46.4 min, p < 0.001) and OSA (+10.5 min, p = 0.009) independently increased ST. A negative COPD × OSA interaction ( p = 0.021) indicated less-than-additive effects, whereas a positive COPD × OSA × PLMS interaction ( p = 0.036) identified the highest desaturation burden. Conclusion: COPD and OSA independently worsen nocturnal hypoxemia, while the coexistence of COPD, OSA, and PLMS confers the greatest desaturation burden, underscoring the importance of evaluating overlapping conditions in clinical assessment.
Jain et al. (Mon,) studied this question.