Severe Obstructive Sleep Apnea May Lead to Worse Post-Stroke Prognosis

In the setting of acute ischemic stroke, severe obstructive sleep apnea (OSA) was associated with poorer functional outcomes than non-severe OSA, according to a small study published in the journal Sleep Medicine.

High comorbidity between stroke and OSA has been reported, however, it remains unclear whether the severity of OSA affects functional outcomes. For the study, researchers assessed the impact of OSA on functional prognosis in the acute phase of stroke and examined quantitative electroencephalography (EEG) markers during sleep in patients with stroke.

The study was conducted at the Second Affiliated Hospital of Soochow University in China between 2015 and 2020. Patients (N=130) who had an ischemic stroke and met the criteria for OSA were recruited. Risk for poor functional outcomes were evaluated on the basis of demographic, clinical, polysomnography, and EEG outcomes. Severe OSA was defined as Apnea-Hypopnea Index (AHI) ≥30/h and poor functional outcomes were defined as modified Rankin Scale (mRS) ≥3 points.

The patient population comprised 109 (87.2 %) men, and mean age, 58 (interquartile range [IQR], 49-66) years. Patients had a body mass index (BMI) of 26 (IQR, 22.8-28.6) kg/m², National Institutes of Health Stroke Scale (NIHSS) at admission was 2 (IQR, 1-3) points, and 13.6% had poor functional prognosis.

A total of 41 (33.3%) patients had severe OSA. Compared with individuals in the non-severe OSA group (n=84; 66.7%), those with severe OSA had higher BMI (28 vs 24, P <.001), more had hypertension (85.4% vs 56%, P =.002), and poor functional prognosis (24.4% vs 8.3%, P =.03). After adjusting for cofounders, severe OSA associated with a 3.6-fold increased risk for poor prognosis (P =.04).

Poor functional prognosis (n=17) was positively related with 3 parameters (odds ratio [OR] range, 1.02-1.12) and negatively related with 4 parameters (OR range, 0.39-0.85) observed during non-rapid eye movement (REM) sleep. It was also positively (OR range, 1.03-1.07) and negatively (OR range, 0.48-0.73) related with 3 parameters each during REM sleep.

In a predictive model, the basic model including age, gender, and NIHSS score predicted poor functional prognosis with an area under the curve (AUC) of 0.873. Adding severe OSA improved the predictive power to an AUC of 0.888. Adding non-REM and REM parameters improved the model to AUCs ranging from 0.914 to 0.939, in which the best model included the delta/alpha power ratio during REM sleep.

This study was likely limited by not including a non-OSA comparator cohort.

These data indicated that severe OSA increased risk for poor functional outcomes following ischemic stroke compared with non-severe OSA.

“Integrating the alteration of quantitative EEG parameters may improve the accuracy of early predictions of functional prognosis in patients with stroke,” the researchers stated.

This article originally appeared on Neurology Advisor