Elsevier

Sleep Medicine

Volume 19, March 2016, Pages 8-12
Sleep Medicine

Original Article
Sleep-disordered breathing among acute ischemic stroke patients in Brazil

https://doi.org/10.1016/j.sleep.2015.11.008Get rights and content

Highlights

  • Obstructive sleep apnea (OSA) is very frequent in Brazilian patients with acute stroke.

  • Severe OSA was associated with a poor long-term functional outcome following stroke.

  • OSA is a treatable condition and therefore its treatment seems to be a potential target to improve outcome of acute stroke patients.

Abstract

Objectives

Sleep-disordered breathing (SDB) is very common in acute stroke patients and has been related to poor outcome. However, there is a lack of data about the association between SDB and stroke in developing countries. The study aims to characterize the frequency and severity of SDB in Brazilian patients during the acute phase of ischemic stroke; to identify clinical and laboratorial data related to SDB in those patients; and to assess the relationship between sleep apnea and functional outcome after six months of stroke.

Methods

Clinical data and laboratorial tests were collected at hospital admission. The polysomnography was performed on the first night after stroke symptoms onset. Functional outcome was assessed by the modified Rankin Scale (mRS).

Results

We prospectively evaluated 69 patients with their first-ever acute ischemic stroke. The mean apnea–hypopnea index (AHI) was 37.7 ± 30.2. Fifty-three patients (76.8%) exhibited an AHI ≥ 10 with predominantly obstructive respiratory events (90.6%), and thirty-three (47.8%) had severe sleep apnea. Age (OR: 1.09; 95% CI: 1.03–1.15; p= 0.004) and hematocrit (OR: 1.18; 95% CI: 1.03–1.34; p= 0.01) were independent predictors of sleep apnea. Age (OR: 1.13; 95% CI: 1.03–1.24; p= 0.01), body mass index (OR: 1.54; 95% CI: 1.54–2.18; p= 0.01), and hematocrit (OR: 1.19; 95% CI: 1.01–1.40; p= 0.04) were independent predictors of severe sleep apnea. The National Institutes of Health Stroke Scale (NIHSS; OR: 1.30; 95% CI: 1.1–1.5; p= 0.001) and severe sleep apnea (OR: 9.7; 95% CI: 1.3–73.8; p= 0.03) were independently associated to mRS >2 at six months, after adjusting for confounders.

Conclusion

Patients with acute ischemic stroke in Brazil have a high frequency of SDB. Severe sleep apnea is associated with a poor long-term functional outcome following stroke in that population.

Introduction

Sleep-disordered breathing (SDB) and cerebrovascular disease (CVD) are highly prevalent worldwide [1], [2]. Recent accumulating clinical and epidemiological evidences suggest a strong causal relationship between them [3], [4], [5], [6], [7], [8]. Obstructive sleep apnea (OSA) is the most common form of SDB and it is characterized by repetitive episodes of partial or complete upper airway obstruction during sleep [9]. A population-based survey study in Brazil identified that around 32% of adults fulfill the criteria for OSA syndrome, according to the International Classification of Sleep Disorders – ICSD-2 [10]. This prevalence is dramatically greater than that reported in other epidemiological studies, which has been partly attributed to specific characteristics of the Brazilian population sample, including a higher proportion of elderly and obese [11].

Several studies have shown that OSA is very frequent in acute stroke patients and has been associated with poor short-term and long-term outcomes [12], [13], [14], [15]. In addition, OSA has been identified as an independent risk factor for stroke [6], [7], [8]. In Brazil, CVD is the leading cause of death and disability, imposing a significant economic and social burden on society [16]. A better understanding of the factors that contribute to adverse outcome of stroke patients in developing countries could guide the search for appropriate interventions to change the course of this dramatic scenario. OSA is a treatable condition and therefore its treatment seems to be a potential target to improve the outcome for acute stroke patients [17], [18], [19]. Unfortunately, there is a lack of data about the relationship between SDB and stroke patients within the Brazilian population. Furthermore, the impact of SDB on functional outcome of stroke patients is still controversial [13], [14], [20].

We sought to analyze the prevalence and severity of SDB in acute ischemic stroke patients in Brazil; to identify clinical and laboratorial data related to the presence and severity of SDB; and to assess the relationship between sleep apnea and functional outcome six months after the cerebrovascular event.

Section snippets

Subjects

Patients with first-ever supratentorial ischemic stroke within 24 h of symptoms' onset were prospectively assessed at the Emergency Department of our University Hospital. Patients with age <18 or >80 years old; stupor or coma; severe chronic obstructive pulmonary disease; clinically decompensated congestive heart failure; baseline oxyhemoglobin saturation <92%; or recent myocardial infarction were excluded. Consecutive patients who fulfilled all the inclusion criteria and none of the exclusion

Results

Sixty-nine patients were enrolled in the present study. The first 29 patients had already been reported in a previous study with a different primary objective [26]. Since then, we were able to expand our sample to improve the power of our analysis. Among all subjects, 52 (75.4%) were men, and the mean age was 60.8 ± 11.8 years. Hypertension was the most frequent risk factor for stroke (71%). History of habitual snoring was retrieved from 51 (73.9%) patients and the mean BMI was 26.3 ± 4.5 kg/m2

Discussion

We found a higher frequency of SBD in Brazilian patients with first-ever ischemic stroke with a clear predominance of obstructive events. According to the previous meta-analysis, more than 60% of stroke patients have SDB and only 7% of them have primarily central apnea [27].

The age of the patient and the hematocrit were independently associated with the presence and the severity of OSA, and BMI was also an independent predictor of severe apnea. While age and BMI are well-known risk factors for

Conflict of interest

The authors report no conflicts of interest.

The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2015.11.008.

. ICMJE Form for Disclosure of Potential Conflicts of Interest form.

Acknowledgements

The authors would like to thank Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP – 2010/04795-0, 2010/20857-5, 2012/51725-2), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – 474295/2010-9, 482721/2013-8).

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