Sleep study measurements predict underlying cardiopulmonary disease

NASHVILLE, Tenn. — Among patients undergoing a sleep study, two oxygenation benchmarks demonstrated utility as screening tools for predicting underlying cardiopulmonary disease, according to study results.

These included average oxygen saturation below 90.1% and more than 10% of total sleep time spent with oxygen saturation below 90%, results showed.

For the study, which was presented at the CHEST Annual Meeting, Yaisa M. Hernandez, MD, of the University of Miami Miller School of Medicine, and a colleague aimed to assess the utility of oxygen saturation — a variable usually measured and reported in a sleep study — as a diagnostic tool for cardiovascular and pulmonary conditions, and to define an appropriate cutoff for screening of underlying diseases.

The researchers conducted a retrospective chart review of 2015 to 2021 data from 123 patients in a community-based hospital. Patients underwent a sleep study — either lab or home-test — with concomitant echocardiogram and pulmonary function test 12 months before or after their sleep study.

Using receiver operating characteristic analysis, researchers determined the diagnostic value of oxygen saturation variables commonly recorded during sleep studies — average oxygen saturation and percentage of total sleep study time in which saturation was below 90%. They evaluated how these variables related to prevalent cardio-pulmonary conditions — including heart failure with reduced ejection fraction with left ventricular ejection fraction (LVEF) less than 40%; diastolic dysfunction; suspected pulmonary arterial hypertension with right ventricular systolic pressure (RVSP) greater than 35 mm Hg; and obstructive, restrictive and mixed respiratory diseases — using a selected cutoff point that represented the larger area under the curve (AUC) for each condition.

Overall, average saturation less than 90.1% showed an average sensitivity of 85.3%, with an AUC 0.686. More than 10% of sleep study time with oxygen saturation below 90% showed an average sensitivity 71.1% and an AUC 0.676.

Results indicated a significant difference in the likelihood of having cardiovascular and pulmonary conditions among patients meeting the cutoffs.

Specifically, the odds were greater among patients with more than 10% of total sleep study time with oxygen saturation below 90% for obstructive disease (OR = 2.67; 95% CI, 1.22-5.82); restrictive disease (OR = 2.18; 95% CI, 1.06-4.48); mixed disease (OR = 4.46; 95% CI, 1.17-17.07); RVSP greater than 35 mm Hg (OR = 2.32; 95% CI, 1.03-5.19); and LVEF less than 40% (OR = 1.11; 95% CI, 1.02-1.21).

“Average saturation below 90.1% and more than 10% of total sleep study time in which oxygen saturation was below 90% are useful screening tools to predict underlying cardiopulmonary disease,” the researchers concluded. “The use of these screening tools in clinical practice is a promising method that could facilitate the early diagnosis of prevalent cardiovascular and pulmonary conditions in patients that undergo a sleep study.”

Reference:

Hernandez YM, et al. Chest. 2022;doi:10.1016/j.chest.2022.08.2117.