Composition of nocturnal hypoxaemic burden and its prognostic value for cardiovascular mortality in older community-dwelling men
Key result
T90 nocturnal hypoxaemic burden predicts cardiovascular mortality in older men, reflecting desaturations and oxygen drifts.
Why the study?
Does nocturnal hypoxaemic burden (T90) predict cardiovascular mortality in older community-dwelling men?
Key Points
- To examine the nocturnal hypoxaemic burden and its potential as a prognostic indicator for cardiovascular mortality in older men.
- Analyzed overnight oximetry data from polysomnograms in 2840 older men from the MrOS Sleep study.
- Calculated oxygen desaturation index (ODI) and time spent below 90% oxygen saturation (T90).
- Performed follow-up over 8.8 years to assess cardiovascular mortality.
- T90 was significantly associated with cardiovascular death (HR 1.21, P < 0.001) and remained significant after adjusting for confounders (HR 1.16, P = 0.004).
- Men with T90 > 12 min had an increased risk of CV mortality (HR 1.59; P = 0.006).
- Non-specific drifts accounted for approximately 20.7% of the variation in T90 but did not improve predictive value when combined with T90desaturation.
Study Design
Type
Cohort
Structured PICO
Does nocturnal hypoxaemic burden (T90) predict cardiovascular mortality in older community-dwelling men?
P
Population
older community-dwelling men
I
Intervention
T90 (nocturnal hypoxaemic burden)
O
Outcome
cardiovascular mortalityhard clinical
Nocturnal hypoxaemic burden (T90) is an independent predictor of cardiovascular mortality in older men, suggesting its potential utility as a clinical risk marker.
Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“The study shows for the first time that poor blood oxygenation during sleep predicts the chance of heart-related death in elderly men. The study also demonstrates that reduced blood oxygenation cannot be attributed to episodic drops in oxygen alone.”
“The study showed that when the men had 12 or more minutes of sleep at low oxygen saturation below 90 per cent this increased the risk of heart-related death by 59 per cent.”
Implication
T90 may aid CV risk stratification in older men; leaves open whether reducing hypoxaemic burden improves outcomes in trials.
Abstract
AIMS: To investigate the composition of nocturnal hypoxaemic burden and its prognostic value for cardiovascular (CV) mortality in community-dwelling older men. METHODS AND RESULTS: We analysed overnight oximetry data from polysomnograms obtained in 2840 men from the Outcomes of Sleep Disorders in Older Men (MrOS Sleep) study (ClinicalTrials.gov Identifier: NCT00070681) to determine the number of acute episodic desaturations per hour (oxygen desaturation index, ODI) and time spent below 90% oxygen saturation (T90) attributed to acute desaturations (T90desaturation) and to non-specific drifts in oxygen saturation (T90non-specific), respectively, and their relationship with CV mortality. After 8.8 ± 2.7 years follow-up, 185 men (6.5%) died from CV disease. T90 [hazard ratio (HR) 1.21, P < 0.001], but not ODI (HR 1.13, P = 0.06), was significantly associated with CV death in univariate analysis. T90 remained significant when adjusting for potential confounders (HR 1.16, P = 0.004). Men with T90 > 12 min were at an elevated risk of CV mortality (HR 1.59; P = 0.006). Approximately 20.7 (5.7-48.5) percent of the variation in T90 could be attributed to non-specific drifts in oxygen saturation. T90desaturation and T90non-specific were individually associated with CV death but combining both variables did not improve the prediction. CONCLUSION: In community-dwelling older men, T90 is an independent predictor of CV mortality. T90 is not only a consequence of frank desaturations, but also reflects non-specific drifts in oxygen saturation, both contributing towards the association with CV death. Whether T90 can be used as a risk marker in the clinical setting and whether its reduction may constitute a treatment target warrants further study.
Discussion
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Cite This Study
Baumert et al. (2018) conducted a cohort in Nocturnal hypoxaemic burden. T90 (nocturnal hypoxaemic burden) was evaluated on Cardiovascular mortality. T90 (nocturnal hypoxaemic burden) is an independent predictor of cardiovascular mortality in older community-dwelling men, reflecting both frank desaturations and non-specific oxygen drifts.