Oxygen-drop burden predicts cardiovascular events
In people with coronary artery disease and sleep apnea, a higher overnight oxygen-drop burden predicted more major heart and stroke events better than event counts.
*Secondary analysis of prospective cohort; Level 1b (OCEBM).
Citation
Peker Y, Celik Y, Zinchuk A, Sands SA, Redline S, Azarbarzin A. Association of hypoxic burden with cardiovascular events: a risk stratification analysis of the Randomized Intervention With CPAP in Coronary Artery Disease and Sleep Apnea cohort. CHEST. 2025;168(6):1481-1493. doi:10.1016/j.chest.2025.07.4081
Background
The usual severity measure for obstructive sleep apnea is the number of breathing pauses per hour, but it may not reflect how much oxygen levels drop. This study tested whether an oxygen-drop burden measure better predicts future serious cardiovascular outcomes.
Patients
368 adults with coronary artery disease after revascularization and moderate-to-severe obstructive sleep apnea.
Intervention
Higher baseline oxygen-drop burden during sleep (above the group median).
Control
Lower baseline oxygen-drop burden (below the median).
Outcome
First major cardiovascular or stroke event (repeat revascularization, heart attack, stroke, or cardiovascular death).
Follow-up Period
Median 4.7 years.
Results
| Comparison |
Outcome |
Effect |
| Higher vs lower oxygen-drop burden (overall) |
Major cardiovascular or stroke event (primary) |
Hazard ratio 1.87 (95% CI, 1.17-2.98); absolute risk 27.2% vs 16.8% (number needed to harm ≈ 10) |
| Higher vs lower oxygen-drop burden (untreated or not adherent) |
Major cardiovascular or stroke event (primary) |
Hazard ratio 1.87 (95% CI, 1.08-3.22) |
| Higher vs lower oxygen-drop burden (with daytime sleepiness) |
Major cardiovascular or stroke event (primary) |
Hazard ratio 2.18 (95% CI, 1.03-4.63) |
“Oxygen-drop burden” combines how often, how deep, and how long oxygen levels fall during sleep breathing pauses.
Limitations
Secondary analysis; few women; limited power for subgroups; adherence analyses may reflect healthier-user bias; results may not generalize beyond coronary artery disease patients.
Funding
Swedish public funders and ResMed; industry support could bias.
Clinical Application
For coronary artery disease patients with sleep apnea, consider oxygen-drop burden (not just event counts) to identify higher-risk patients and prioritize sleep-focused risk reduction.
