Oct 5 2012
By Lucy Piper, Senior medwireNews Reporter
Untreated severe obstructive sleep apnea (OSA) is associated with an increased risk for cardiovascular death in the elderly, say researchers.
This increased risk for cardiovascular death was largely due to an increase in deaths from stroke and heart failure, with no increased risk from ischemic heart disease, the researchers add.
However, continuous positive airway pressure (CPAP) treatment was effective in reducing the increased risk.
"Our finding that adequate CPAP treatment is associated with significant reductions in cardiovascular mortality in patients with OSA has important implications, especially given the increasing elderly population," said senior researcher Miguel Ángel Martinez-García (La Fe University and Polytechnic Hospital, Valencia, Spain) in a press statement.
A total of 939 individuals aged at least 65 years were assessed for OSA over a median of 69 months. Sleep assessments were conducted with either full standard polysomnography (43%) or respiratory polygraph according to Spanish guidelines (57%).
In all, 784 of the participants had OSA and 503 were receiving CPAP, with CPAP use of at last 4 hours daily considered as good adherence to treatment. Among those patients not receiving CPAP, 108 had mild-to-moderate OSA (apnea-hypopnea index [AHI] of 15-29) and 173 had severe OSA (AHI ≥30). The remaining participants with an AHI below 15 served as controls.
The study findings, published in the American Journal of Respiratory and Critical Care Medicine show that, compared with the control group, patients with untreated, severe OSA were 2.25 times more likely to die from a cardiovascular cause.
For untreated patients with mild-to-moderate OSA, the risk for cardiovascular mortality was increased compared with controls, but not significantly.
CPAP-treated patients with OSA had a risk for cardiovascular death similar to that of the control group.
The results were similar for a subgroup of patients aged at least 75 years and among patients who initiated CPAP treatment, compliance was independently associated with a reduced risk for cardiovascular mortality.
"We have provided the first evidence that severe untreated OSA is associated with cardiovascular mortality in elderly people of both sexes," the team concludes.
"Although additional research is required, we believe this study is an important step in developing evidence for this common but relatively understudied disorder in the elderly."
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