Egyptian Journal of Chest Diseases and Tuberculosis (2016) 65, 259–263
H O S T E D BY
The Egyptian Society of Chest Diseases and Tuberculosis
Egyptian Journal of Chest Diseases and Tuberculosis www.elsevier.com/locate/ejcdt www.sciencedirect.com
ORIGINAL ARTICLE
Excessive daytime sleepiness among patients with metabolic syndrome Adel Salah Bediwy a,*, Yousuf M. Mansour a, Ehab A. Abo Ali b a b
Chest Department, Faculty of Medicine, Tanta University, Egypt Public Health and Community Medicine Department, Faculty of Medicine, Tanta University, Egypt
Received 23 July 2015; accepted 9 August 2015 Available online 21 August 2015
KEYWORDS Excessive day time sleepiness; Metabolic syndrome; Sleep apnea
Abstract Background: Metabolic syndrome is a medical disorder that predisposes to cardiovascular diseases. Excessive daytime sleepiness (EDS) is a common finding in patients with metabolic syndrome. Aim: To assess the presence of EDS among subjects with metabolic syndrome and to find its correlations with apnea hypopnea index (AHI), Hamilton depression rating score (HDRS), body mass index (BMI), age and fasting plasma glucose (FPG). Method: 76 patients with metabolic syndrome were evaluated for EDS by Epworth sleepiness score (ESS) and for sleep apnea by polysomnography. Results: 22 subjects (28.9%) had EDS, 37 subjects (48.7%) had sleep apnea and 28 subjects (36.8%) had depression. ESS showed no significant association with AHI while it showed significant associations with each of HDRS, BMI, age and FPG. Conclusions: Other explanations of EDS in subjects with metabolic syndrome can be related to obesity, depression, or diabetes rather than to sleep apnea. Subjects with metabolic syndrome should be screened for EDS regardless of sleep apnea. Ó 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of The Egyptian Society of Chest Diseases and Tuberculosis. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
Introduction Metabolic syndrome is a combination of the medical disorders that, when present together, increase the risk of developing cardiovascular disease and diabetes. Some studies have shown the prevalence in the USA to be an estimated 25% of the population, and prevalence increases with age [1]. * Corresponding author. E-mail address:
[email protected] (A.S. Bediwy). Peer review under responsibility of The Egyptian Society of Chest Diseases and Tuberculosis.
Metabolic syndrome, also known as insulin resistance syndrome or syndrome X, is recognized as a constellation of obesity, glucose intolerance, dyslipidemia, and hypertension. Over the past several decades, there has been a substantial increase in the prevalence of metabolic syndrome, coinciding with the increased prevalence of obesity [2]. Obstructive sleep apnea (OSA) is a clinical condition characterized by recurrent episodes of complete obstruction (apnea) or partial obstruction (hypopnea) of the upper airway, leading to increased negative intrathoracic pressure, sleep fragmentation, and intermittent hypoxia during sleep [3].
http://dx.doi.org/10.1016/j.ejcdt.2015.08.010 0422-7638 Ó 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of The Egyptian Society of Chest Diseases and Tuberculosis. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
260 In the United States, the prevalence of OSA is estimated to be 3–7% in men and 2–5% in women. Among patients with a body mass index greater than 28, OSA is present in 41% [4,5]. OSA has implications beyond disrupted sleep. It is increasingly recognized as an independent risk factor for cardiac, neurologic, and peri-operative morbidities [6]. It is also associated with high incidence of some psychiatric disturbances such as depression [7]. Some studies showed that 50–60% of people who are obese and patients with the metabolic syndrome have OSA [8]. The prevalence of OSA is even higher in obese patients with diabetes mellitus [9]. Excessive daytime sleepiness may be related to the extent of adiposity, the distribution of adiposity, or metabolic, inflammatory, physical, mental, or psychological disturbances experienced by obese subjects. It may be also related to the increased incidence of OSA in these patients [10]. Excessive daytime sleepiness compromises quality of life due to the impairment it causes in work performance, interpersonal relations, and cognitive and neuropsychological functions, in addition to causing a higher risk of car accidents, and metabolic and cardiovascular diseases [11–14]. So the presence of excessive daytime sleepiness in subjects with metabolic syndrome has to be assessed and explained. The aim of this study was to assess excessive daytime sleepiness in subjects with metabolic syndrome and to find the correlation between daytime sleepiness as measured by the Epworth sleepiness scale and both apnea hypopnea index, Hamilton Depression Rating Scale, body mass index, waist circumference, age and fasting plasma glucose (FPG). Subjects and methods Patients who presented to outpatient clinics in Tanta University Hospitals and had the diagnostic criteria of the metabolic syndrome according to the International Diabetes Federation (IDF) consensus worldwide definition [15] and who agreed to share in the study were included. Study sample was taken with a convenient sample technique until recruitment of 76 subjects was achieved in a period of six months. The study protocol was approved by the local ethics committee of Tanta Faculty of Medicine and written consents were signed by all the participants. The IDF consensus worldwide definition of the metabolic syndrome [15] 2006 is: Central obesity (defined as increased waist circumference with ethnicity-specific values) and any two of the following (NB: If BMI is >30 kg/m2, central obesity can be assumed and waist circumference does not need to be measured): Raised triglycerides: >150 mg/dL (1.7 mmol/L), or specific treatment for this lipid abnormality. Reduced HDL cholesterol: 85 mmHg, or treatment of previously diagnosed hypertension. Raised fasting plasma glucose (FPG): >100 mg/dL (5.6 mmol/L), or previously diagnosed type 2 diabetes.
A.S. Bediwy et al. Exclusion criteria: We excluded patients with thyroid or other endocrinal disorders other than diabetes mellitus, asthma, COPD, restrictive lung disease, lung cancer, sarcoidosis, chronic liver or kidney diseases, and previous psychiatric diagnosis or who were on antidepressant medications. Patients with alcohol or drug addiction, cerebral infarction, unstable angina, myocardial infarction during the previous 3 months, and congestive heart failure were also excluded. The followings were carried for all participants: Thorough history taking: with special care to other co-morbidities, drug use, smoking status, substance and alcohol abuse. Examination: general and chest examination to exclude patients with exclusion criteria, assess body mass index (BMI), vital signs, and waist circumference. Routine laboratory tests: to help diagnosing metabolic syndrome, and to exclude patients with exclusion criteria. Chest X ray postero–anterior view. Epworth sleepiness scale: was used to assess daytime sleepiness. Patients rated the likelihood of falling asleep in eight specific situations on a 0–3 scale, with 0 meaning no chance at all of falling asleep, and 3 representing a high chance of falling asleep. Thus, the scale goes from 0 to 24. A score of ten suggests excessive daytime sleepiness [16]. The Hamilton Depression Rating Scale (HDRS): it is an inventory employed to detect and identify the intensity or severity of the signs and symptoms of depression; 17 questions are divided into two categories. The first category consists of nine questions scored on a five-point scale; the second category consists of eight questions rated on a three-point scale. The total score is computed reflecting the degree of symptom severity. A score of >10 indicates impairment [17]. All patients underwent overnight polysomnography using the AliceÒ 5 Polysomnography System (Philips Respironics, Murraysville, PA) with Alice Sleepware Software. This polysomnogram consisted of overnight recording of left and right electrooculogram, chin electromyogram, left and right tibialis anterior electromyogram, central and occipital EEG, electrocardiogram, airflow measurement, body position sensor, snoring sensor and microphone, respiratory effort belt (abdominal and thoracic), and pulse oximetry. The sleep study began around 11 pm and the duration of the study was at least 5 h. The patients were instructed to avoid sleeping during the daytime before the study and to avoid alcohol, sedatives, hypnotics, and other medicines affecting sleep. Statistical analysis: It was performed with the Statistical Package for Social Sciences (SPSS), version 16.0 (Chicago, IL, USA). Data are presented as mean (±SD) values. Appropriate test of significance was used when needed. Significant statistical difference was considered when p < 0.05. Results The study included 76 subjects with metabolic syndrome who agreed to share in the study. Demographic, anthropometric and clinical characteristics of the studied subjects are shown in Table 1.
Excessive daytime sleepiness among patients with metabolic syndrome Table 1 Demographic, anthropometric and clinical characteristics of the studied group. Characteristics
Study group (n = 76) No.
%
Age in years 43.03 ± 14.32 18– 30– 40– 50– P60
15 15 16 17 13
19.7 19.7 21.1 22.4 17.1
Gender Males Females
40 36
52.6 47.4
BMI 33.8 ± 1.9 kg/m2 30–34.9 P35
44 32
Waist circumference High risk Low risk
44 32
261
Table 2 Epworth sleepiness score (ESS) in relation to demographic, anthropometric and clinical characteristics of the studied group. Characteristics
Epworth sleepiness score (ESS)
Test of significance
Positive (n = 22)
v2
Negative (n = 54)
p
No.
%
No.
%
Age in years 100 mg/dL 6100 mg/dL
17 5
77.3 22.7
28 26
51.9 48.1
4.183 0.041*
ESS 8.3 ± 5.7 Positive Negative
22 54
28.9 71.1
AHI 13.62 ± 14.2 Nil Mild (5-) Moderate (15-) Severe (P30)
39 8 16 13
51.3 10.5 21.1 17.1
HDRS 15.34 ± 13.77 Positive Negative
28 58
36.8 63.2
FPG 158.89 ± 44.8 mg% >100 mg/dL 6100 mg/dL
45 31
59.2 40.8
BMI: body mass index. ESS: Epworth sleepiness score. AHI: Apnea hypopnea index. HDRS: Hamilton depression rating scale. FPG: Fasting plasma glucose.
Epworth sleepiness score (ESS) values showed no significant association with apnea hypopnea index (AHI) while it showed significant association with both HDRS, BMI and waist circumference, age and fasting plasma glucose (FPG) (p < 0.05) (Table 2). AHI showed significant positive correlations with HDRS, BMI and waist circumference, age and FPG (Table 3). It was noticed that AHI values in subjects having excessive daytime sleepiness and those without excessive daytime sleepiness were 17.3 ± 15.8 and 12.1 ± 13.4 respectively without any statistically significant difference (t = 1.35 and p = 0.19). Discussion This study has shown that Epworth sleepiness score (ESS) in subjects with metabolic syndrome was 8.263 ± 5.7. The
BMI: body mass index. AHI: Apnea hypopnea index. HDRS: Hamilton depression rating scale. FPG: Fasting plasma glucose. * Significant statistical difference.
Table 3 Correlations between AHI and other studied parameters. Correlations between AHI and
r
p
HDRS BMI Waist circumference Age FPG
0.47 0.77 0.755 0.404 0.364
