Association of Incident Cardiovascular Disease With Progression of Sleep-Disordered Breathing
Prospective data suggest that sleep-disordered breathing (SDB) enhances risk for incident and recurrent cardiovascular disease (CVD). Does incident CVD cause or worsen SDB?
The Sleep Heart Health Study (SHHS) is a cohort of individuals age >40 years recruited from subjects in several ongoing cohort studies of CV and obstructive pulmonary diseases in the United States. A total of 2,721 SHHS participants without CVD at baseline underwent two polysomnograms 5 years apart. Incident CVD events, including myocardial infarction (MI), congestive heart failure (CHF), and stroke, were ascertained and adjudicated. The relation of incident CVD to change in apnea-hypopnea index between the two polysomnograms was tested with general linear models, with adjustment for age, sex, race, study center, history of diabetes mellitus, change in body mass index (BMI), change in neck circumference, percent sleep time spent in supine sleep, and time between the two polysomnograms.
The mean (standard deviation) age was 62 (10) years, 57% were women, and 23% were minorities. Incident CVD occurred in 95 participants between the first and second polysomnograms. Compared with participants without incident CVD, those with incident CVD experienced larger increases in apnea-hypopnea index (AHI) between polysomnograms. The difference in adjusted mean AHI change between subjects with and without incident CVD was 2.75 events per hour (95% confidence interval [CI], 0.26-5.24; p = 0.032), which persisted after subjects with central sleep apnea were excluded. Compared with participants without incident CVD, participants with incident CVD had greater increases in both mean obstructive and central apnea indices, by 1.75 events per hour (95% CI, 0.10-1.75; p = 0.04) and by 1.07 events per hour (95% CI, 0.40-1.74; p = 0.001), respectively. The association of change in AHI with CHF was only half as large as its association with incident MI.
In a diverse, community-based sample of middle-aged and older adults, incident CVD was associated with worsening SDB over 5 years.
There is no evidence that incident CVD is causal for SDB with the exception of CHF and strokes, which may be associated with both central sleep apnea and obstructive sleep apnea. The authors found that CVD is associated with increased AHI in subjects with baseline AHI >5, but not in subjects with AHI <5. This suggests that CVD could worsen SDB in subjects already affected by SDB. Interestingly, incident CVD was associated with increased AHI in subjects with baseline BMI <25 kg/m2, but not in subjects with BMI >25 kg/m2, which suggests that increase in weight may obscure the effect of CVD on SDB progression. The potential influence of treatment of CVD on SDB, such as beta-blockers, was not assessed.
Keywords: Myocardial Infarction, Middle Aged, Heart Failure, Cardiovascular Diseases, Sleep Apnea Syndromes, United States
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