CPAP Reduces Long-Term Cardiovascular Risk in Patients with Obstructive Sleep Apnea
Multiple lines of research show patients with moderate to severe obstructive sleep apnea are at significantly increased risk of suffering a cardiovascular event.1-5 It is also clear that over the short term, continuous positive airway pressure (CPAP) treatment significant reduces sleepiness, blood pressure, and motor vehicle accidents, and enhances sleep-related quality of life in this population.6 What has been missing is evidence of long term cardiovascular risk benefit, if any, on sustained CPAP use.7 Work presented at the virtual SLEEP 2021 annual meeting in June may finally provide some of the evidentiary support cardiologists have been waiting to see.
CPAP therapy decreased the risk of a cardiovascular event by 44%
Dr. Diego Mazzotti and colleagues analyzed the large and detailed Kaiser Permanente Southern California health system electronic health records over a period of nearly two years and identified 45,927 patients with apnea-hypopnea index (AHI) results.8 The researchers assorted the records into three groups; 11,145 without sleep apnea, 13,898 with sleep apnea and any CPAP use, and 20,884 patients with sleep apnea and no record of CPAP use. Importantly, “any CPAP use” was defined broadly; in this group, the median CPAP use was 2.5 hours per day with an interquartile range of 0.7 to 5.0 hours per day. Rather modest CPAP use, to be sure, but in line with other real world studies examining CPAP adherence. All patients included in the analysis had reasonably continuous insurance coverage had no evidence of cardiovascular disease for at least 1 year prior to diagnosis of obstructive sleep apnea. Cox proportional hazards model accounted for age, sex, BMI, race, Charlson comorbidity index, and the use of hypertension or hyperlipidemia medications. Cardiovascular events of interest were myocardial infarction, stroke, unstable angina, heart failure or death from a cardiovascular cause.
Over a median of 262 days, patients with moderate to severe obstructive sleep apnea had a 71% higher likelihood of experiencing a cardiovascular event than those without obstructive sleep apnea (p=0.016). This result was expected from many previous retrospective and prospective studies. However, if patients with any severity of obstructive sleep apnea used a CPAP device for any length of time, their risk of an incident cardiovascular event was essentially reduced by a third (p=0.016). When the same analysis was restricted to patients with moderate or severe obstructive sleep apnea, any CPAP use reduced the risk of a cardiovascular event by an impressive 44% (p=0.002).8
Identifying patients with obstructive sleep apnea must be a priority for cardiologists
While this is an observational study, its large size and long duration highlight the importance of treating as many patients with obstructive sleep apnea as possible. Untreated moderate to severe sleep apnea is clearly a major risk factor for a cardiovascular event. The cardiovascular benefits of CPAP treatment are increasingly clear for patients with any degree of sleep apnea, but especially so for those with moderate or severe disease. Moreover, CPAP therapy is cost effective in patients with moderate or severe obstructive sleep apnea and is generally regarded as safe.9,10
Overcoming the barriers to CPAP implementation: A Role for home sleep apnea testing?
Unfortunately, implementing CPAP can be clinically challenging. Poor CPAP adherence is a common problem, as these recent data also indicate, yet even modest CPAP use appears to confer a cardiovascular benefit. The initial and often most difficult barrier to overcome is to get patients to undergo polysomnography in a sleep laboratory. Traditionally patients must spend one night (e.g., 9 pm to 7 am) in a sleep center for diagnostic purposes and a second night to titrate CPAP (or bilevel positive airway; BPAP) settings. However, the number of sleep centers and the number of testing and titration slots within those centers are limited. This creates geographical and scheduling barriers that only very motivated patients will overcome. If patients do schedule and attend their appointment at the sleep lab, sleeping “normally” in a sleep center is its own challenge.
Home sleep apnea testing, which tends to be much more favorable to patients for comfort, convenience, and logistical reasons, correlates very well with in-laboratory, “gold standard” polysomnography studies11 for sleep apnea diagnosis. Patients can receive an accurate diagnosis and titration with unattended sleep apnea monitoring in the comfort of their own bedrooms. Home sleep apnea testing is certainly something to consider for any patient who complains of daytime sleepiness, nighttime gasping events, or snoring.
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2. Lee CH, Sethi R, Li R, et al. Obstructive Sleep Apnea and Cardiovascular Events After Percutaneous Coronary Intervention. Circulation. 2016;133(21):2008-2017. 10.1161/CIRCULATIONAHA.115.019392
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