Obstructive Lung Disease and Obstructive Sleep Apnea (OLDOSA) cohort study: 10-year assessment

Abstract

Study objectives: Asthma, chronic obstructive pulmonary disease (COPD), and obstructive sleep apnea (OSA) are very prevalent disorders. Their coexistence in the same individual has an unclear effect on natural history and long-term outcomes.

Methods: The OLDOSA (Obstructive Lung Disease and Obstructive Sleep Apnea) cohort enrolled 4,980 veterans with an acute hospitalization and in whom asthma, COPD, OSA, overlapping conditions, or none of these disorders at baseline had been diagnosed. Pulmonary function, polysomnography, positive airway pressure (PAP) recommendations and adherence, and vital status were collected and analyzed. Various proportional hazards models were built for patients with OSA to test the effect of PAP therapy on survival.

Results: Ten-year all-cause cumulative mortality rate was 52.8%; median time to death was 2.7 years. In nonoverlapping asthma, OSA and COPD, mortality rates were 54.2%, 60.4%, and 63.0%, respectively. The overlap syndromes had the following mortality: COPD-OSA 53.2%, asthma-COPD 62.1%, asthma-OSA 63.5%, and triple overlap asthma-COPD-OSA 67.8%. In patients with OSA not on PAP therapy, after adjustment for age, comorbidities, and lung function, risk of death was 1.34 (1.05-1.71) times higher than those undergoing treatment. Similarly, in patients with OSA nonadherent to PAP therapy the adjusted risk of death was 1.78 (1.13-2.82) times higher versus those using it at least 70% of nights and more than 4 hours nightly.

Conclusions: In this large longitudinal cohort of hospitalized veterans with high comorbid burden, asthma, COPD, OSA and their overlap syndromes had very high long-term mortality. In patients with OSA, PAP initiation and superior therapeutic adherence were associated with significantly better survival.

Keywords: asthma; chronic obstructive pulmonary disease (COPD); mortality; obstructive lung disease; obstructive sleep apnea; overlap syndrome; positive airway pressure.

Figure 1. Study diagram.

Proportional Venn diagram of the OLDOSA Cohort (n = 4,980). Patient population outside the circles and inside the rectangle is represented by patients with no OSA, COPD, or asthma. Asthma, COPD, and OSA “only” = nonintersecting or nonoverlapping disorders. ACO = asthma and COPD (no sleep apnea), AOS = asthma and OSA (no COPD), COPD = chronic obstructive pulmonary disease, OSA = obstructive sleep apnea, OS = COPD and OSA (no asthma), TO = triple overlap of asthma, COPD and OSA.

Figure 2. Survival plots by conditions.

Kaplan-Meier survival plot by condition (P < .0001, log rank test). Triple overlap (asthma + COPD + OSA) had the worst survival. Asthma (green); COPD, chronic obstructive pulmonary disease (red); OSA, obstructive sleep apnea (blue); none, none of the three conditions (dotted black); COPD + OSA (no asthma; brown); Asthma + COPD (no OSA; pink); asthma + OSA (no COPD; light green); asthma + COPD + OSA (purple).

Figure 3. Survival plots by PAP therapy.

Kaplan-Meier survival plots of patients with OSA on PAP therapy (green), OSA not on PAP therapy (red), P < .0001, log-rank test. OSA = obstructive sleep apnea, PAP = positive airway pressure.

Figure 4. Survival plots by PAP adherence.

Kaplan-Meier survival plots in patients with OSA, PAP adherent (bright green) and PAP nonadherent (dark green), P = .00071, log rank test. OSA = obstructive sleep apnea, PAP = positive airway pressure.