Figure 4.

Kaplan-Meier survival curves for outcomes among COPD patients without OSA (COPD group), patients with COPD and coexisting OSA (overlap group), and patients with overlap syndrome treated with CPAP since enrolment (overlap with CPAP group). Percentage survival (A), percentage of severe COPD exacerbation-free survival curves among the three study groups (B). The differences between COPD only and COPD with OSA treated with CPAP are statistically significant from patients with COPD and untreated OSA (P<0.001). COPD, chronic obstructive pulmonary disease; OSA, obstructive sleep apnoea; CPAP, continuous positive airway pressure. Reproduced from (58).