Sex-related Differences in Cardiometabolic Outcomes Associated With Obstructive Sleep Apnea: A Review

"Sleep disordered breathing and ECG R-wave to radial artery pulse delay, The Multi-Ethnic Study of Atherosclerosis"

BACKGROUND

Electrocardiography R-wave to radial artery pulse delay (RRD) represents pulse transit time inclusive of pre-ejection period (PEP) and arterial pulse propagation time. RRD is proposed to largely reflect arterial stiffness when PEP is accounted for (shorter RRD = higher arterial stiffness). Sleep disordered breathing (SDB) causes intermittent hypoxemia and sympathetic activation, which negatively influences vascular function. We aimed to examine the association of measures of SDB with RRD.

METHODS

Our sample consisted of participants in the Multi-Ethnic Study of Atherosclerosis without prevalent cardiovascular disease who underwent a daytime arterial elasticity exam, cardiac magnetic resonance imaging (MRI), and overnight polysomnography. SDB measures of interest included apnea hypopnea index (AHI) and oxygen desaturation index (ODI) (N = 1173). RRD was regressed on each measure of SDB separately, with adjustment for other cardiovascular risk factors as well as for correlates of the PEP, another component of RRD, by including cardiac MRI measures of contractility and preload.

RESULTS

In multivariate analysis, among measures of SDB, ODI, a marker of intermittent hypoxemia, was inversely associated with RRD (β = -60.2 msec per SD [15.5/hr], p = 0.04). No significant association was found with AHI. In gender stratified analyses, ODI and AHI were predictive of RRD in men only (β = -111.3 msec per SD [15.5/hr], p = 0.01 and β = -100.3 msec per SD [16.1/hr], p = 0.02 respectively).

CONCLUSION

Severity of SDB as measured by ODI was associated with RRD, a marker of arterial stiffness. Thus, association of RRD with measures of SDB appears to be gender-dependent.

Sleep-disordered breathing and electrocardiographic QRS-T angle: The MESA study

INTRODUCTION

Sleep-disordered breathing (SDB) has been linked to sudden cardiac death (SCD) but the mechanism is unclear. Abnormal QRS-T angle, a novel electrocardiographic (ECG) marker of ventricular repolarization, has been linked to adverse cardiovascular outcomes including SCD. We hypothesized that individuals with SDB have more pronounced abnormality in QRS-T angle.

METHODS

We performed a cross-sectional analysis from the Multi-Ethnic Study of Atherosclerosis (MESA) Exam Sleep ancillary study. We calculated the odds ratio (OR) of abnormal frontal and spatial QRS-T angle (defined as >sex-specific 95th percentile thresholds) related to the apnea-hypopnea index (AHI) using logistic regression, adjusting for demographics, body habitus, cardiovascular risks, and prevalent cardiovascular disease. Linear associations between AHI and frontal and spatial QRS-T angle, separately, were also examined using multiple regression models.

RESULTS

A total of 1,804 participants (mean age 67.9 (±9.0) years, 55.3% women and 64.1% non-whites) were included in the study. Sleep-disordered breathing was common among participants (median AHI 8.6 events/hr IQR [3.2-19.5/hr]). Higher AHI was associated with the odds of abnormal frontal (≥81° in men and ≥79° in women) and spatial QRS-T angle (≥129.7° in men and ≥115.9° in women; OR [95%CI]: 1.25 [1.02-1.51], p = 0.03; 1.23 [1.01-1.50], p = 0.04 respectively per 1 SD [16.8 events/hr] increase in AHI). Similarly, linear associations were observed (frontal QRS-T angle: beta coefficient: 2.30° [0.92, 3.66], p = 0.001; spatial QRS-T angle: beta coefficient: 2.16° [0.67, 3.64], p = 0.005).

CONCLUSION

In a racially/ethnically diverse community cohort, severity of SDB is associated with abnormal ventricular repolarization as measured by QRS-T angle.

Diagnosis and treatment of sleep apnoea in women with schizophrenia

BACKGROUND

Obstructive sleep apnoea (OSA) is often overlooked in the context of schizophrenia because its hallmark, daytime sleepiness, is so easily attributable to antipsychotic drugs. This is a special problem for women.

AIMS

To underscore the importance of diagnosing and treating OSA in women with schizophrenia.

METHODS

A review of the recent literature (search terms: Obstructive Sleep Apnoea; Schizophrenia; Women (or Gender); Obesity; Antipsychotics; Continuous Positive Airway Pressure (CPAP)) as it applies to a composite case vignette taken from the files of a specialty clinic that treats women with psychosis.

RESULTS

The rate of OSA in women who are both obese and postmenopausal is very similar to that of men. Family history, smoking, and the use of tobacco, alcohol and of antipsychotic medication increase the risk. Despite reluctance, patients with schizophrenia generally agree to undergo sleep studies. Compliance with CPAP is difficult, but can be aided by the physician and is, on the whole, relatively high in women. CPAP improves sleep parameters and may also improve cardiometabolic and cognitive indices, although this still needs to be more fully researched.

CONCLUSION

Schizophrenia and untreated OSA are both associated with high mortality rates in women as well as men.