Association Between Exertional Dyspnea and OSA

Dyspnea increases mortality and remains unexplained in 15% of patients. Although OSA is linked to reduced exercise capacity during cardiopulmonary exercise testing, the association between dyspnea and OSA remains uncertain.

Is there an association between exertional dyspnea and OSA in the general population? What are the polysomnographic OSA-related measures associated with exertional dyspnea?

We used data from a prospective cohort study of the general population conducted in an urban area. Participants underwent polysomnography and completed a respiratory questionnaire. Logistic regression models were used to determine the association between self-reported dyspnea (modified Medical Research Council Dyspnea scale ≥ 1) and OSA categories or apnea-hypopnea index (AHI) cutoffs. We performed an adjusted model for sex, BMI, age, FEV₁, psychiatric disorders, cardiac and respiratory disorders, and smoking history.

We included 1,200 participants (mean age, 62.1 years; 54% female), of whom 515 (42.9%) reported exertional dyspnea. The adjusted model revealed a positive association between exertional dyspnea and AHI ≥ 15 events/h (OR, 1.57; 95% CI, 1.13-2.19), AHI ≥ 30 events/h (OR, 1.72; 95% CI, 1.06-2.78), moderate OSA (OR, 1.60; 95% CI, 1.04-2.46), and severe OSA (OR, 2.25; 95% CI, 1.28-3.96). Moreover, in the adjusted model, dyspnea was associated with AHI, respiratory disturbance index, respiratory pulse wave amplitude drop index, sleep apnea-specific pulse-rate response, respiratory arousal index, and oxygen desaturation index 3%.

Our results suggest that exertional dyspnea is associated with moderate and severe OSA, potentially due to heightened autonomic and cortical responses to increased respiratory efforts. Further research is needed to assess the effectiveness of OSA treatment on dyspnea in patients with OSA.