Older adults suffering from severe obstructive sleep apnea (OSA) are at an increased risk of dying from heart disease, claims a new study. The mortality risk can be significantly reduced with continuous positive airway pressure (CPAP) treatment.
"Although the link between OSA and cardiovascular mortality is well established in younger patients, evidence on this relationship in the elderly has been conflicting," Miguel Angel Martinez-Garcia, lead author of the study from La Fe University and Polytechnic Hospital in Valencia, Spain, said.
"In our study of 939 elderly patients, severe OSA not treated with CPAP was associated with an increased risk of cardiovascular mortality especially from stroke and heart failure, and CPAP treatment reduced this excess of cardiovascular mortality to levels similar to those seen in patients without OSA," Martinez-Garcia said.
All subjects in this prospective, observational study were 65 years of age or older. Median follow-up was 69 months.
Sleep studies were conducted with either full standard polysomnography or respiratory polygraphy following Spanish guidelines. OSA was defined as mild-to-moderate or severe.
Patients with AHI less than 15 acted as controls. CPAP use 4 hours daily was considered as good adherence to treatment.
Compared with the control group, the adjusted hazard ratios for cardiovascular mortality were 2.25 (CI, 1.41 to 3.61) for patients with untreated severe OSA, 0.93 (CI, 0.46 to 1.89) for patients treated with CPAP and 1.38 (CI, 0.73 to 2.64) for patients with untreated mild-to-moderate OSA.
Similar results were observed among the subgroup of patients 75 years of age. Among patients who initiated CPAP treatment, compliance was independently associated with a reduced risk of cardiovascular mortality.
The study had a few limitations, including that the study was not randomized, the reduced statistical power in the subgroup analyses, and the use of respiratory polygraphy to diagnose OSA in a number of patients. Strengths included being the large study size including exclusively elderly patients and the long follow-up.
"This is the first large-scale study to examine the impact of OSA on cardiovascular mortality in a series including exclusively elderly patients and assess the effectiveness of CPAP treatment in reducing this risk," Dr. Martinez-Garcia said.
"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," Martinez-Garcia added.
The study has been published in the Journal of Respiratory and Critical Care Medicine.