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 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 14  |  Issue : 2  |  Page : 274-278

Prevalence and pattern of obstructive sleep apnea in chronic obstructive pulmonary disease patients from northern India


1 Department of General Medicine, SHKM Government Medical College, Nuh, Haryana, India
2 Department of Paediatrics, SHKM Government Medical College, Nuh, Haryana, India
3 Department of Community Medicine, SHKM Government Medical College, Nuh, Haryana, India

Date of Submission11-Feb-2021
Date of Acceptance03-May-2021
Date of Web Publication31-May-2021

Correspondence Address:
Dr. Rakesh Tank
Department of General Medicine, SHKM Government Medical College, Nuh, Haryana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/kleuhsj.kleuhsj_25_21

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  Abstract 


BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, hyperinflation, and ventilation-perfusion mismatch. It is now considered as a systemic disease. The prevalence of obstructive sleep apnea (OSA) in COPD is variable with a paucity of literature from Indian subcontinent.
AIM: This study was conducted to observe the regional prevalence and pattern of OSA in patients of COPD.
MATERIALS AND METHODS: The present prospective study was carried out in the Department of Internal Medicine, Pt. B.D. Sharma, PGIMS, Rohtak, for a period of 20 months, i.e. during July 2012 to February 2014. Patients seeking care at the Department of Internal Medicine and diagnosed with COPD formed the study population. COPD patients stable for at least 6 weeks were included in this study. Mild COPD patients, ischemic heart disease patients, any comorbid state, known case of OSA, and patients having COPD with acute exacerbation were excluded. The prescreening tools for the identification of OSA are Berlin sleep questionnaire and the Epworth sleepiness scale (ESS). Polysomnography was done using Somnologica studio 3.3.2 Embla N7000 sleep unit system.
RESULTS: OSA with apnea–hypopnea index (AHI) ≥5/h was present in 10 out of 40 participants (25.0%). Berlin scores were found to be 0.10 ± 0.03 and 0.70 ± 0.04 in nonsleep-disordered breathing (SDB) and SDB participants, respectively. ESS scores were observed to be 2.60 ± 0.82 and 7.90 ± 2.51 between non-SDB and SDB participants, respectively. The difference in AHI between patients with non-SDB and SDB was statistically highly significant (1.36 ± 0.37, 13.41 ± 3.40; P < 0.001). Variation in numbers of apnea in rapid eye movement (REM) (1.20 ± 0.68, 9.9 ± 1.87) and non-REM (4.47 ± 1.48, 50.50 ± 8.70) between two groups of participants was found to be statistically significant (P < 0.05) and highly significant (P < 0.001), respectively. Average O2 saturation and O2 desaturation events were also varied significantly between two groups of patients.
CONCLUSIONS: The prevalence of OSA in COPD patients was found to be in the higher range. Sleep was significantly distorted in all its aspects in patients of COPD. ESS was found efficient in screening the patients of COPD for coexistent OSA. Berlin's questionnaire can be used to evaluate patients of overlap syndrome.

Keywords: Chronic obstructive pulmonary disease, obstructive sleep apnea, overlap syndrome, pattern, prevalence


How to cite this article:
Tank R, Tank P, Singh A. Prevalence and pattern of obstructive sleep apnea in chronic obstructive pulmonary disease patients from northern India. Indian J Health Sci Biomed Res 2021;14:274-8

How to cite this URL:
Tank R, Tank P, Singh A. Prevalence and pattern of obstructive sleep apnea in chronic obstructive pulmonary disease patients from northern India. Indian J Health Sci Biomed Res [serial online] 2021 [cited 2021 Jun 17];14:274-8. Available from: https://www.ijournalhs.org/text.asp?2021/14/2/274/317402




  Introduction Top


Obstructive sleep apnea (OSA) syndrome is a common disorder characterized by recurrent upper airway collapse during sleep.[1] The inspiratory efforts to overcome occlusion lead to arousal, sleep fragmentation, and oxy-hemoglobin desaturation.[2] The coexistence of OSA and chronic obstructive pulmonary disease (COPD) has been termed as “overlap syndrome.”

In patients with COPD requiring long-term oxygen therapy, the coexistence of moderate to severe OSA has been seen in 16% of population.[3] Similarly, the incidence of COPD in patients with OSA has been found to be from 9% to 29%.[4],[5],[6],[7] This seemingly high prevalence promoted a speculation that OSA and COPD were linked by a common mechanism or common pathophysiology.

Varied results emerging out of various studies have created a controversy about burden of OSA in COPD patients. According to best of our knowledge, burden of OSA in COPD patients has not been closely investigated by the subject experts in the state of Haryana. Paucity of literature also warrants this study. Therefore, the present study was planned to analyze and ascertain the prevalence of OSA in COPD patients from Northern India. An additional objective was to study sleep pattern of sleep-disordered breathing (SDB) patients.


  Materials and Methods Top


The present cross-sectional study was carried out in the Department of Internal Medicine, Pt.B.D. Sharma PGIMS Rohtak for a period of 20 months, i.e. during July 2012–February 2014. Patients seeking care at the Department of Internal Medicine and diagnosed with COPD formed the study population. COPD patients stable for at least 6 weeks were included in this study. Mild COPD patients, ischemic heart disease patients, any comorbid state, known case of OSA, and patients having COPD with acute exacerbation were excluded. Permission of Institutional review the board was sought before the commencement of the study (IRB/PGIMS/Med./2011/55; dated 18-04-2011).

Pt. B.D. Sharma PGIMS Rohtak is a tertiary care teaching hospital equipped with ultra-modern multisuper specialty facilities and apex referral unit of Haryana state. The hospital receives major chunk of its patients not only from Haryana but also from neighboring states, especially Rajasthan, Punjab, Delhi, and Uttar Pradesh. Thus, this tertiary care hospital provided us a perfect base to study such an objective.

Purposive sampling technique was adopted. A total of 59 patients were enrolled in this study but at the end, 40 cases and 10 controls were selected following below mentioned algorithm [Figure 1]. COPD was diagnosed as per standard guidelines, i.e. global initiative for obstructive lung disease guidelines.[8]
Figure 1: Algorithm depicting methodology for the current study

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Study participants were subjected to detailed history taking including smoking habits, alcohol consumption, routine blood investigations, chest radiography, echocardiography to rule out left ventricular failure and underwent anthropometry measurements, and ENT examination. Spirometry was carried out on the study participants, and parameters recorded were forced expiratory volume in the first second (FEV1) in liters, forced vital capacity (FVC) in liters, and FEV1/FVC% (FEV1/FVC). All the selected patients were given a questionnaire based upon “Epworth sleepiness scale (ESS)” to determine clinically about any disturbance of sleep and Berlin Questionnaire to identify persons at risk for OSA syndrome. Polysomnography was done using Somnologica studio 3.3.2 Embla N7000 sleep unit system (2005) in all the patients, selected for the study.

The prescreening tools for the identification of OSA were Berlin sleep questionnaire (BSQ) and the ESS. BSQ was used to identify persons at risk for sleep apnea syndrome, and ESS was used to determine the severity of person's daytime sleepiness.

The study adhered to the tenets of the Declaration of Helsinki for research in humans. Informed consent was obtained from study participants after discussing advantages and risks. Permission of Institutional review board was sought before the commencement of the study (IRB/PGIMS/Med./2011/55). All the questionnaires along with other relevant data were manually checked and were then coded for computer entry. After compilation of the collected data, analysis was done using the Statistical Package for the Social Sciences (SPSS), version 20 (IBM, Chicago, Illinois, USA). The results were expressed using appropriate statistical methods. One-way analysis of variance, Fisher's exact, and Student t-test were used to test the level of significance. Difference between patients with apnea–hypopnea index (AHI) below and above 5/h in the mean nocturnal saturation was tested using Mann–Whitney test. A two-tailed P < 0.05 was considered statistically significant.


  Results Top


Data of 40 participants were included in the final analyses.

Prevalence of obstructive sleep apnea in chronic obstructive pulmonary disease patients

OSA with AHI ≥5/h was present in 10 out of 40 participants (25.0%).

Pattern of obstructive sleep apnea in chronic obstructive pulmonary disease patients

Males were more vulnerable to develop OSA as compared to females. Similarly, smokers frequently developed OSA as compared to chulha users. Other anthropometric and spirometric patterns are presented below. Berlin scores were found to be 0.10 ± 0.03 and 0.70 ± 0.04 in non-SDB and SDB participants, respectively. ESS scores were observed to be 2.60 ± 0.82 and 7.90 ± 2.51 between non-SDB and SDB participants, respectively [Table 1].
Table 1: Demographic, anthropometric, and spirometric patterns of obstructive sleep apnea in chronic obstructive pulmonary disease patients

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The difference in AHI between patients with non-SDB and SDB was statistically highly significant (1.36 ± 0.37, 13.41 ± 3.40; P < 0.001). Variation in numbers of apnea in rapid eye movement (REM) (1.20 ± 0.68, 9.9 ± 1.87) and non-REM (4.47 ± 1.48, 50.50 ± 8.70) between two groups of participants was found to be statistically significant (P < 0.05) and highly significant (P < 0.001), respectively. Average O2 saturation and O2 desaturation events were also varied significantly between two groups of patients [Table 2].
Table 2: Various sleep parameters among study participants in nonsleep-disordered breathing and sleep-disordered breathing groups

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  Discussion Top


Coexistence of both COPD and OSA was termed by Flenley as the “Overlap” Syndrome.[9] In our study, the prevalence of OSA in COPD patients is found to be 25.0%. Some authors have reported higher prevalence[4] whereas others have reported much lower prevalence.[5],[6],[7]

Multiple mechanisms may be implicated in the pathophysiology between OSA and COPD. End-expiratory lung volume has an important impact on pharyngeal mechanics, and thus, the hyperinflation associated with COPD may protect against upper airway collapse.[10] Conversely, because lung elastic recoil is thought to be important, and destruction of lung parenchyma seen in emphysema may reduce caudal traction forces thought to stabilize the upper airway. The presence of OSA in patients with COPD increases the risk of exacerbation and shortens the time to the first exacerbation.[11]

We observed significant variation in numbers of apneas in REM (1.20 ± 0.68, 9.9 ± 1.87) and non-REM (4.47 ± 1.48, 50.50 ± 8.70) between two groups of participants. Average O2 saturation and O2 desaturation events were also varied significantly between the two groups of patients. Patients with severe emphysema are known to have poor sleep quality. Krachman et al. studied 25 patients with COPD and emphysema and found that sleep quality was poor; nocturnal oxygenation desaturations (NODs) were common and the measurements of respiratory mechanics and function as well as NODs were important predictors of sleep quality.[12]

In our study, ESS scores in SDB and non-SDB patients (7.9 ± 2.51, 2.60 ± 0.82) were compared and we found a highly significant difference (P < 0.001). Mean ESS in the study group by Bednarek et al. was 6.1 ± 3.6,[13] but he as well as Krieger et al.[14] found no significance of ESS in relation to OSA. Assessment by ESS score has been found to be highly variable when repeated in the same population over time period due to difficulty in quantifying subjective sleepiness.[15] Even with these negative remarks, such high significance cannot be ignored and ESS can be used as a screening tool for OSA in screen patients of COPD.

Body mass index (BMI) of SDB patients was comparable to that of non-SDB patients (P = 0.059). It implies that OSA pathogenesis in our study group is independent of BMI. Similar findings were noticed in many studies when they tried to correlate BMI in patients of COPD with overlap syndrome.[14] Dixon et al.[16] found neck circumference to be the first most and waist circumference the second most single clinical measure for predicting SDB. While comparing parameters of patients having OSA and non-OSA COPD, we have found no significant difference (P = 0.086) in neck circumference and waist-hip ratio (P = 0.187). Reason for such discordance can be the regional variations and the mechanisms of OSA being independent of the above anthropometric measures making them a less sensitive tool for screening our type of population for SDB.

We assessed participants at risk of sleep apnea syndrome by Berlin's Questionnaire. Berlin scores were found to be 0.10 ± 0.30 and 0.70 ± 0.48 in non-SDB and SDB participants, respectively. These differences were observed to be statistically significant. For comparison, we found no study on COPD participants evaluating Berlin's questionnaire. These findings suggest that Berlin's questionnaire can be used to evaluate patients for OSA, especially in those having COPD.


  Conclusions Top


On the basis of empirical evidence of the current study, it can be summarized that the prevalence of OSA in COPD patients was found to be in the higher range. Sleep was significantly distorted in all its aspects in patients of COPD. ESS was found to be efficient in screening the patients of COPD for coexistent OSA. Berlin's questionnaire can be used to evaluate patients of OSA, especially those having COPD.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Young T, Palta M, Dempsey J, Skatrud J, Weber S, Badr S. The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med 1993;328:1230-5.  Back to cited text no. 1
    
2.
Deegan PC, McNicholas WT. Pathophysiology of obstructive sleep apnoea. Eur Respir J 1995;8:1161-78.  Back to cited text no. 2
    
3.
Machado MC, Vollmer WM, Togeiro SM, Bilderback AL, Oliveira MV, Leitão FS, et al. CPAP and survival in moderate-to-severe obstructive sleep apnoea syndrome and hypoxaemic COPD. Eur Respir J 2010;35:132-7.  Back to cited text no. 3
    
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Turcani P, Skrickova J, Pavlik T, Janousova E, Orban M. The prevalence of obstructive sleep apnea in patients hospitalized for COPD exacerbation. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2015;159:422-8.  Back to cited text no. 4
    
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Chaouat A, Weitzenblum E, Krieger J, Ifoundza T, Oswald M, Kessler R. Association of chronic obstructive pulmonary disease and sleep apnea syndrome. Am J Respir Crit Care Med 1995;151:82-6.  Back to cited text no. 5
    
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de Miguel J, Cabello J, Sánchez-Alarcos JM, Alvarez-Sala R, Espinós D, Alvarez-Sala JL. Long-term effects of treatment with nasal continuous positive airway pressure on lung function in patients with overlap syndrome. Sleep Breath 2002;6:3-10.  Back to cited text no. 6
    
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Resta O, Foschino Barbaro MP, Brindicci C, Nocerino MC, Caratozzolo G, Carbonara M. Hypercapnia in overlap syndrome: Possible determinant factors. Sleep Breath 2002;6:11-8.  Back to cited text no. 7
    
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Millman RP, Knight H, Kline LR, Shore ET, Chung DC, Pack AI. Changes in compartmental ventilation in association with eye movements during REM sleep. J Appl Physiol (1985) 1988;65:1196-202.  Back to cited text no. 8
    
9.
Flenley DC. Sleep in chronic obstructive lung disease. Clin Chest Med 1985;6:651-61.  Back to cited text no. 9
    
10.
Squier SB, Patil SP, Schneider H, Kirkness JP, Smith PL, Schwartz AR. Effect of end-expiratory lung volume on upper airway collapsibility in sleeping men and women. J Appl Physiol (1985) 2010;109:977-85.  Back to cited text no. 10
    
11.
Marin JM, Soriano JB, Carrizo SJ, Boldova A, Celli BR. Outcomes in patients with chronic obstructive pulmonary disease and obstructive sleep apnea: The overlap syndrome. Am J Respir Crit Care Med 2010;182:325-31.  Back to cited text no. 11
    
12.
Krachman SL, Chatila W, Martin UJ, Permut I, D'Alonzo GE, Gaughan JP, et al. Physiologic correlates of sleep quality in severe emphysema. COPD 2011;8:182-8.  Back to cited text no. 12
    
13.
Bednarek M, Plywaczewski R, Jonczak L, Zielinski J. There is no relationship between chronic obstructive pulmonary disease and obstructive sleep apnea syndrome: A population study. Respiration 2005;72:142-9.  Back to cited text no. 13
    
14.
Krieger AC, Patel N, Green D, Modersitzki F, Belitskaya-Levy I, Lorenzo A, et al. Respiratory disturbance during sleep in COPD patients without daytime hypoxemia. Int J Chron Obstruct Pulmon Dis 2007;2:609-15.  Back to cited text no. 14
    
15.
Nguyen AT, Baltzan MA, Small D, Wolkove N, Guillon S, Palayew M. Clinical reproducibility of the Epworth Sleepiness Scale. J Clin Sleep Med 2006;2:170-4.  Back to cited text no. 15
    
16.
Dixon JB, Schachter LM, O'Brien PE. Predicting sleep apnea and excessive day sleepiness in the severely obese: Indicators for polysomnography. Chest 2003;123:1134-41.  Back to cited text no. 16
    


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