Nightly OSA Variability Linked to Uncontrolled Hypertension

Poorly managed sleep apnea can lead to uncontrolled high blood pressure, and those most at risk have wide-ranging variability in their night-to-night OSA severity. This can be overlooked or misdiagnosed during standard clinical testing, a study from Flinders University, Adelaide, Australia warns.  

Standard OSA testing generally is done over a single night in a sleep lab. Given the reported night-to-night variability in OSA, standard testing may underestimate OSA severity or miss the diagnosis entirely.

“Regardless of their overall OSA average severity, people with increased night-to-night variability in the amount of sleep apnea are at a 50% to 70% increased likelihood of having uncontrolled hypertension and variable blood pressure – a confirmed risk factor for cardiovascular events, all-cause mortality, vascular organ damage, atrial fibrillation and dementia,” says lead author Dr Bastien Lechat.

The study of shifting OSA severity was made possible by using an under-mattress sleep sensor technology that allows for multi-night, in-home, non-invasive monitoring [Withings Sleep Analyzer]. Data from 12,287 adults over approximately 180 nights with about 30 repeat blood pressure tests were included in the analyses. 

The sensor technology measured both OSA severity and night-to-night variation in OSA severity, leading researchers to make comparisons with current single night sleep assessments and possible misdirected management and care.  

Night-to-night variability in severity was determined from the standard deviation of the estimated  Apnea-Hypopea Index across recording nights. Uncontrolled hypertension was defined as mean systolic blood pressure ≥140 mmHg and/or mean diastolic blood pressure ≥90 mmHg. 

In addition to reinforcing recent evidence of nigh-to-night variation in OSA severity, “our study suggests that high night-to-night variability in OSA severity may also be an important contributor to cardiovascular disease,” said Danny Eckert, PhD. “Therefore, there is considerable potential to incorporate new simplified monitoring approaches to aid current single-night diagnostics, which are labor-intensive and costly.”