Utility of Epworth Sleepiness Scale ( ESS ) in predicting the presence of Sleep Related Breathing Disorders ( SRBD ) in patients in Routine Respiratory Clinical Service

Background Many patients attending routine respiratory clinical service in developing countries also present with complains of daytime sleepiness and sleep abnormalities. A large proportion of them might have Sleep Related Breathing Disorders (SRBD) and as such, it is underestimated. Within this background we conducted a study to explore the presence of SRBD among patients presenting with symptom complex of respiratory diseases in Routine Respiratory Clinical Service by use of Epworth Sleepiness Scale (ESS). Material and Methods A cross-sectional study of 50 patients with respiratory symptom complex was conducted in respiratory clinical service of Division of Pulmonary, Critical Care and Sleep Medicine at B. P. Koirala Institute of Health Sciences (BPKIHS) from 2014-2015. Targeted Comprehensive Sleep History and Epworth Sleepiness Scale (ESS) were used to recognize the presence of SRBD among these patients. Results 74% patients had ESS score ≥10. Mean ESS was 12.32 (±4.76). 72% subjects had daytime fatigue, 62% loud snoring, 58% daytime sleepiness and 46% sleep fragmentation. ESS ≥10 reflected excessive daytime sleepiness (sensitivity 86.67%; 95% CI, 69.28 – 96.24; specificity 45%, 95% CI, 23.06 – 68.47; PPV 70.27%, 95% CI, 53.02 – 84.13; NPV 69.23%, 95% CI, 38.57 – 90.91). Conclusion Epworth Sleepiness Scale has utility in predicting SRBD in patients with respiratory symptom complex with high overall predictive accuracy. It can be used in routine clinical care to identify and predict patients having Sleep Related Breathing Disorder and refer them to clinical sleep services for further evaluation.


Introduction
Respiratory clinics in the developing countries are burdened with myriad presentations of common conditions such as Bronchial Asthma, Chronic Obstructive Pulmonary Disease (COPD), Bronchiectasis and Interstitial Lung Diseases.With the ageing process comes the predisposition to disorders of sleep such as sleep-related breathing disorders (SRBD) and sleep disturbances such as loud snoring, excessive daytime sleepiness, daytime fatigue, morning headaches, and nocturnal oxygen desaturations [1].There is a high prevalence of sleep disorders in subjects with chronic respiratory illnesses [2].Respiratory comorbidities may mask the common manifestations of sleep disorders, leading to underestimation of its burden in subjects with respiratory diseases, that may cause poorer quality of life and outcomes despite adequate treatment of the chronic respiratory condition [3,4,5,6].There is scarcity of data on the burden of SRBD in the Nepalese population with respiratory symptom complex, and with the polysomnography test not being readily available, a need to screen sleep disorders in this group of patients is imperative.The Epworth Scale for measuring daytime sleepiness correlated well with results of overnight polysomnography [7,8] and has been used a screening tool for excess daytime sleepiness.Within this background, the study aimed to explore the presence of SRBD among patients with symptom complex of respiratory diseases in routine respiratory clinical service by use of Epworth Sleepiness Scale.

Discussion
The study has dealt with the issue of screening for sleep disturbances and sleep related breathing disorders (SRBD) in patients with symptom complex of respiratory diseases presenting to routine respiratory clinical service in a tertiary hospital in eastern Nepal.For this purpose, the Epworth Sleepiness Scale (ESS), a targeted comprehensive sleep history using a sleep disturbance-related questionnaire, and Polysomnography were used to identify presence of sleep related breathing disorder in patients presenting with respiratory symptom complexes.While most studies available have dealt with the screening of sleep disorders in particular respiratory disorders such as chronic obstructive pulmonary disease or bronchial asthma or the Overlap Syndrome, the present study includes all patients with a respiratory symptom complex.About a third of the patients visiting health care facilities in developing countries complain of respiratory symptoms, with 28% Nepalese population having respiratory symptoms, [10] and more than 50% of the population suffer from some sleep disturbance, the prevalence of sleep related breathing disorders (SRBD) could be higher.In routine respiratory clinical services in Nepal, sleep disorders are uncommon diagnoses since seldom do such patients present with a sleep related problem.In fact, unmasking sleep related abnormalities from the myriad respiratory manifestations are a clinical challenge.Daytime fatigue was the most predominant sleep disturbance seen in our study population followed by loud snoring.In fact, patients with respiratory disease who also had problem of loud snoring were at higher risk for development of sleep related breathing disorder (OR 8.582, p value = 0.006, 95% CI 1.842 -39.989).The Epworth Sleepiness Scale (ESS) [

Conclusion
The study concludes that the Epworth Sleepiness Scale has good utility in predicting the presence of sleep related breathing disorder in patients with symptom complex of respiratory disease who visit the routine respiratory clinical services with high predictive accuracy and conducting a simple self-answered sleep disturbance abnormality questionnaire as an adjunct to the ESS strengthens the probability of presence of SRBD in such patients.The Epworth Sleepiness Scale can be used in routine respiratory clinical care to predict presence of sleep related breathing disorder and refer them to clinical sleep services for further evaluation.

Sleep-Related Breathing Disorder (SRBD):
This hospital based cross-sectional study was conducted in the Division of Pulmonary, Critical Care and Sleep Medicine at the Department of Internal Medicine of B. P. Koirala Institute of Health Sciences, a tertiary care university hospital in Eastern Nepal, from May 1, 2014 to September 30, 2015.The Institute's Ethical Review Board approved the study.

Table 1 .
Epworth Sleepiness Scale score in patients with respiratory symptom complex attending routine respiratory clinical service

Table 2 .
Sleep related disturbances in patients with respiratory symptom complex attending routine respiratory clinical service

Table 3 .
Utility , may likely have coexistent sleep related breathing disorders (SRBD), and such patients need to be investigated with detailed sleep studies.The study does have limitations in that it does not use a Class 1 polysomnograph, which would have higher accuracy in diagnosis of sleep related breathing disorders, but limitation of such resources is unavoidable in developing countries.