Update on obstructive sleep apnea and its relation to COPD

Association between preserved ratio impaired spirometry and sleep apnea in a Chinese community

OBJECTIVE

This study investigated the association between obstructive sleep apnea (OSA) and preserved ratio impaired spirometry (PRISm) in a community population.

METHODS

Baseline data from a prospective cohort study, the Predictive Value of Combining Inflammatory Biomarkers and Rapid Decline of FEV1 for COPD (PIFCOPD), were used for cross-sectional analysis. Participants aged 40-75 years were recruited from the community and their demographic information and medical history were collected. The STOP-Bang questionnaire (SBQ) was used to assess the risk of OSA. Pulmonary function tests were performed using a portable spirometer (COPD-6) and forced expiratory volume in 1 s (FEV1) and 6 s (FEV6) were measured. Routine blood, biochemical, high-sensitivity C-reactive protein (hs-CRP), and interleukin-6 tests were also performed. The pH of the exhaled breath condensate was determined.

RESULTS

A total of 1183 participants were enrolled, of which 221 with PRISm and 962 with normal lung function. The neck circumference, waist-to-hip ratio, hs-CRP concentration, proportion of males, cigarette exposure, number of current smoker, high risk of OSA, and prevalence of nasal and ocular allergy symptoms were significantly higher in the PRISm group than in the non-PRISm group (p < .05). Logistic regression showed that the risk of OSA (odds ratio, 1.883; 95% confidence interval, 1.245-2.848), waist-to-hip ratio, current smoking, and prevalence of nasal allergy symptoms were independently associated with PRISm after correcting for age and sex.

CONCLUSION

These findings showed that OSA prevalence is independently associated with PRISm prevalence. Further studies should confirm the relationship between systemic inflammation in OSA, localized inflammation of the airways, and impaired lung function.

Evaluating the Relationship of Airflow Obstruction in COPD with Severity of OSA Among Patients with Overlap Syndrome

Background

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are common diseases affecting millions worldwide. These two diseases have a complex relationship that is not well understood. Previous small studies suggest an inverse relationship of disease severity of OSA with COPD airflow obstruction.

Objective

The aim of this study was to determine if a relationship exists between severity of airflow obstruction in COPD and severity of OSA via apnea hypopnea index obtained during an in-lab baseline polysomnogram using a large quaternary care center cohort.

Methods

From November 2015 through December 2018, 273 patients with confirmed COPD via spirometry and OSA via in-lab baseline polysomnogram were included.

Conclusion

No associations were noted between severity of airflow obstruction in COPD and disease severity of OSA. Given the heterogeneity of these diseases, further exploration of a relationship within disease subtypes is warranted.

Chronic Pain in Patients with Chronic Obstructive Pulmonary Disease: A Cross Sectional Study

Background

Many individuals with chronic obstructive pulmonary disease (COPD) report suffering from chronic pain, which affects their quality of life. This study aimed to determine the prevalence, characteristics and impact of chronic pain in patients with COPD, and to explore its possible predictive and aggravating factors.

Materials and Methods

It was a cross-sectional study. Male individuals with COPD responded to a questionnaire, including mMRC, CAT, Brief Pain Inventory (BPI) (composed of Worst pain, Pain Severity Score (PSS) and Pain Interference Score (PIS)), and Hospital Anxiety and Depression Scale. Patients were divided into group 1 (G1) with chronic pain, and group 2 (G2) without chronic pain.

Results

Sixty eight patients were included. The general prevalence of chronic pain was 72.1% (CI95%:10.7%). The most common site of pain was the chest (54.4%). Analgesics were used in 38.8%. Patients from G1 had more hospital admissions in the past (OR=6.4[1.7-23.4]). Three variables were associated to pain in the multivariate analysis: socio-economic level (OR=4.6[1.1-19.2]), hospital admissions (OR=0.087[0.017-0.45]), and CAT (OR=0.18[0.05-0.72]). Dyspnea was associated to PIS (p<0.005). A correlation was found between PSS and PIS (r=0.73). Six patients (8.8%) retired because of pain. Patients who had CAT≥10 were more in G1 (OR=4.9[1.6-15.7]). CAT was correlated to PIS (r=0.5). G1 demonstrated higher anxiety scores (p<0.05). There was a moderate positive correlation between depression symptoms and PIS (r=0.33).

Conclusion

Pain should be systematically assessed in COPD patients, regarding its high prevalence. New guidelines should take into consideration pain management to ameliorate patients' quality of life.

Association between comorbid sleep apnoea-hypopnoea syndrome and prognosis of intensive care patients: a retrospective cohort study

OBJECTIVE

In this study, we investigated the association between comorbid sleep apnoea-hypopnoea syndrome (SAHS) and the prognosis of patients in an intensive care unit (ICU) to determine whether this relationship varies between different disease subgroups.

METHODS

We conducted a retrospective cohort study using publicly available information from the critical care database Medical Information Mart for Intensive Care III. Adults (≥18 years of age) who attended the ICU for the first time were enrolled. Demographic information and clinical data were obtained from each patient. The primary outcome was 30-day mortality after ICU admission, and the secondary outcomes were in-hospital and ICU mortality. Multivariate logistic regression and Cox regression analyses were used to examine the associations between SAHS comorbidities and the research outcomes. Propensity score matching was used to adjust for potential confounding variables.

RESULTS

Of the 32 989 patients enrolled, 1918 (5.81%) were diagnosed with SAHS as a comorbid condition. Patients with SAHS had a significantly lower 30-day mortality rate compared with those without SAHS (5.27% vs 13.65%, respectively; p<0.001). The frequency of chronic obstructive pulmonary disease, cerebral disease, cardiovascular disease, hypertension, diabetes mellitus and renal failure was significantly different between the two groups. Patients with SAHS demonstrated significantly longer survival compared with patients without SAHS. Multivariate Cox proportional hazards regression identified a significant relationship between SAHS and mortality within 30 days (adjusted HR=0.610, 95% CI 0.499 to 0.747, p<0.0001).

CONCLUSION

SAHS as a comorbid condition decreases the risk of 30-day mortality, in-hospital mortality and ICU mortality among ICU patients.

Validation of the brief international classification of functioning, disability, and health core set for obstructive pulmonary disease in the Chinese context

In order to determine the validity of the International Classification of Functioning, Disability, and Health brief Core Set for Obstructive Pulmonary Disease (ICF-OPD) for the assessment of functioning and environmental factors in Chinese chronic OPD (COPD) patients, we conducted a cross-sectional study with a convenience sample of 100 COPD patients. Data were collected using common questionnaires for COPD patients (Modified British Medical Research Council Questionnaire, COPD Assessment Test, St George’s Respiratory Questionnaire (SGRQ)), the Brief ICF Core Set for OPD, and the comprehensive ICF checklist. All except one category of the Brief ICF-OPD Core Set were confirmed in our evaluation of its content validity, but there is a high prevalence of problems in 8 categories that were not considered in the Brief ICF-OPD Core Set. The functioning-related components of the Brief ICF-OPD Core Set largely performed similarly to SGRQ in terms of differentiating between patients with different disease severity. Moreover, high correlations between the Brief ICF-OPD Core Set overall score and component scores with the respective SGRQ scales and moderate correlations between ICF-OPD Core Set overall score and component scores and lung function parameters. This study largely confirmed content, known group, and convergent validity of the ICF-OPD.

Influence of Chronic Obstructive Pulmonary Disease and Moderate-To-Severe Sleep Apnoea in Overnight Cardiac Autonomic Modulation: Time, Frequency and Non-Linear Analyses

Chronic obstructive pulmonary disease (COPD) is one of the most prevalent lung diseases worldwide. COPD patients show major dysfunction in cardiac autonomic modulation due to sustained hypoxaemia, which has been significantly related to higher risk of cardiovascular disease. Obstructive sleep apnoea syndrome (OSAS) is a frequent comorbidity in COPD patients. It has been found that patients suffering from both COPD and OSAS simultaneously, the so-called overlap syndrome, have notably higher morbidity and mortality. Heart rate variability (HRV) has demonstrated to be useful to assess changes in autonomic functioning in different clinical conditions. However, there is still little scientific evidence on the magnitude of changes in cardiovascular dynamics elicited by the combined effect of both respiratory diseases, particularly during sleep, when apnoeic events occur. In this regard, we hypothesised that a non-linear analysis is able to provide further insight into long-term dynamics of overnight cardiovascular modulation. Accordingly, this study is aimed at assessing the usefulness of sample entropy (SampEn) to distinguish changes in overnight pulse rate variability (PRV) recordings among three patient groups while sleeping: COPD, moderate-to-severe OSAS, and overlap syndrome. In order to achieve this goal, a population composed of 297 patients were studied: 22 with COPD alone, 213 showing moderate-to-severe OSAS, and 62 with COPD and moderate-to-severe OSAS simultaneously (COPD+OSAS). Cardiovascular dynamics were analysed using pulse rate (PR) recordings from unattended pulse oximetry carried out at patients’ home. Conventional time- and frequency- domain analyses were performed to characterise sympathetic and parasympathetic activation of the nervous system, while SampEn was applied to quantify long-term changes in irregularity. Our analyses revealed that overnight PRV recordings from COPD+OSAS patients were significantly more irregular (higher SampEn) than those from patients with COPD alone (0.267 [0.210–0.407] vs. 0.212 [0.151–0.267]; p < 0.05) due to recurrent apnoeic events during the night. Similarly, COPD + OSAS patients also showed significantly higher irregularity in PRV during the night than subjects with OSAS alone (0.267 [0.210–0.407] vs. 0.241 [0.189–0.325]; p = 0.05), which suggests that the cumulative effect of both diseases increases disorganization of pulse rate while sleeping. On the other hand, no statistical significant differences were found between COPD and COPD + OSAS patients when traditional frequency bands (LF and HF) were analysed. We conclude that SampEn is able to properly quantify changes in overnight cardiovascular dynamics of patients with overlap syndrome, which could be useful to assess cardiovascular impairment in COPD patients due to the presence of concomitant OSAS.

Predictors of Sleep Apnea in the Canadian Population

Older age, obesity, hypertension, snoring, and excessive daytime sleepiness have been associated with sleep apnea. The objective of this study was to determine the prevalence (crude and adjusted), as well as the risk factors, of sleep apnea in the adult Canadian population. Data from the 2009 Sleep Apnea Rapid Response (SARR) questionnaire were used to identify the risk factors, and all sleep-related questions in the SARR questionnaire were used. The outcome variable of interest was health professional-diagnosed sleep apnea. Covariates of interest were demographic variables, population characteristics, respiratory and cardiovascular diseases, and enabling resources. The multiple logistic regression model adjusted for the clustering effect was used to analyze the data. Sleep apnea was diagnosed in 858,913 adults (3.4% of the population), and more men (65.4%) than women (34.6%) were diagnosed with sleep apnea. Multivariable logistic regression analysis indicated that age (45 and older), loud snoring, sudden awakening with gasping/choking (rare/sometimes and once or more a week), and nodding off/falling asleep in driving in the past 12 months were significantly associated with diagnosed sleep apnea. Predictive probability demonstrated that in overweight and obese persons, ≥15 minutes of daily exercise significantly decreased the risk of diagnosed sleep apnea. The conclusion of this study is that in the Canadian population, sleep apnea is associated with older age, loud snoring, and sleeping problems. The protective effect of exercise warrants further investigation.

Assessment of automated analysis of portable oximetry as a screening test for moderate-to-severe sleep apnea in patients with chronic obstructive pulmonary disease

BACKGROUND

The coexistence of obstructive sleep apnea syndrome (OSAS) and chronic obstructive pulmonary disease (COPD) leads to increased morbidity and mortality. The development of home-based screening tests is essential to expedite diagnosis. Nevertheless, there is still very limited evidence on the effectiveness of portable monitoring to diagnose OSAS in patients with pulmonary comorbidities.

OBJECTIVE

To assess the influence of suffering from COPD in the performance of an oximetry-based screening test for moderate-to-severe OSAS, both in the hospital and at home.

METHODS

A total of 407 patients showing moderate-to-high clinical suspicion of OSAS were involved in the study. All subjects underwent (i) supervised portable oximetry simultaneously to in-hospital polysomnography (PSG) and (ii) unsupervised portable oximetry at home. A regression-based multilayer perceptron (MLP) artificial neural network (ANN) was trained to estimate the apnea-hypopnea index (AHI) from portable oximetry recordings. Two independent validation datasets were analyzed: COPD versus non-COPD.

RESULTS

The portable oximetry-based MLP ANN reached similar intra-class correlation coefficient (ICC) values between the estimated AHI and the actual AHI for the non-COPD and the COPD groups either in the hospital (non-COPD: 0.937, 0.909-0.956 CI95%; COPD: 0.936, 0.899-0.960 CI95%) and at home (non-COPD: 0.731, 0.631-0.808 CI95%; COPD: 0.788, 0.678-0.864 CI95%). Regarding the area under the receiver operating characteristics curve (AUC), no statistically significant differences (p >0.01) between COPD and non-COPD groups were found in both settings, particularly for severe OSAS (AHI ≥30 events/h): 0.97 (0.92-0.99 CI95%) non-COPD vs. 0.98 (0.92-1.0 CI95%) COPD in the hospital, and 0.87 (0.79-0.92 CI95%) non-COPD vs. 0.86 (0.75-0.93 CI95%) COPD at home.

CONCLUSION

The agreement and the diagnostic performance of the estimated AHI from automated analysis of portable oximetry were similar regardless of the presence of COPD both in-lab and at-home. Particularly, portable oximetry could be used as an abbreviated screening test for moderate-to-severe OSAS in patients with COPD.

Sleep Apnea and Obstructive Airway Disease in Older Men: Outcomes of Sleep Disorders in Older Men Study

STUDY OBJECTIVES

To evaluate the association between obstructive airway disease (OAD) and sleep apnea in older men.

METHODS

A community-based cross-sectional study of 853 community-dwelling older men (mean age 80.7 ± 4.1 years [range 73 to 90]) across 6 centers in the United States from the Outcomes of Sleep Disorders in Older Men Study. Sleep was objectively measured using full in-home polysomnography and lung function was objectively measured using spirometry. The association of OAD (pre-bronchodilator FEV1/FVC ratio < 0.7 and FEV1 < 80% predicted) and sleep apnea (apnea-hypopnea index [AHI] ≥ 15 events/hour) was assessed using logistic regression.

RESULTS

OAD and sleep apnea were identified in 111 (13.0%) and 247 (29.0%) men, respectively. In univariate analysis, participants with OAD had a lower AHI (mean ± SD; 8.7 ± 11.7 vs. 12.7 ± 13.8, P = 0.0009) and a lower prevalence of sleep apnea (14.4 vs. 31.1%, P = 0.0003) compared to participants without OAD. OAD remained independently associated with a lower odds of sleep apnea (odds ratio 0.30, 95% CI 0.16 to 0.55, P = 0.0001) after adjustment for demographics, body composition, smoking, and potential mediators (arousal index, time spent in rapid eye movement sleep). Individuals with OAD and sleep apnea (n = 16) had an increased arousal index and lower oxygen saturation level as compared to individuals with OAD alone (P values < 0.05).

CONCLUSIONS

Obstructive airway disease was associated with a lower prevalence of sleep apnea in a cohort of community-dwelling elderly men, and unexplained by differences in adiposity or sleep architecture. Although uncommon in this cohort, coexisting sleep apnea and OAD was associated with increased sleep fragmentation and nocturnal oxygen desaturation compared to OAD alone.

Impact of overlap syndrome on severity of acute exacerbation of chronic obstructive pulmonary disease

BACKGROUND

The severity of exacerbation in chronic obstructive pulmonary disease (COPD) due to the overlap of obstructive sleep apnea syndrome (OSAS) is not known.

AIMS

To find out the 1) severity of acute exacerbation of COPD (AECOPD) in patients with overlap syndrome compared to only COPD, 2) prevalence of overlap syndrome in AECOPD, and 3) clinical characteristics of COPD compared to overlap syndrome.

MATERIALS AND METHODS

Fifty-one patients admitted with AECOPD were classified into; Mild exacerbation: Normal arterial blood gases (ABG) treated with antibiotics, Moderate: Normal ABG treated with parenteral corticosteroids, Severe: Type 1 respiratory failure, Very severe: Type 2 respiratory failure with normal pH and Life-threatening: Type 2 respiratory failure with pH <7.35. They were evaluated for OSAS with full polysomnography after the exacerbation subsided and analysed depending on presence or absence of overlap syndrome.

RESULTS

The majority of only COPD cases (26/38) had mild and moderate exacerbations whereas majority of overlap patients (9/13) had severe, very severe and life-threatening exacerbations (statistically significant, P = 0.021). Of 51 patients, 13 had OSAS i.e. the prevalence of overlap in AECOPD was 25.5%. The mean BMI in only COPD and overlap syndrome was 20.70 ± 8.03 kg/m(2) and 31.82 ± 5.80 kg/m(2) (P < 0.001), respectively. Metabolic syndrome was recorded in 2/36 (5.3%) patients in only COPD and 6/13 (46.2%) patients in overlap (P < 0.001).

CONCLUSION

Overlap syndromes are more likely have respiratory failure compared to only COPD during AECOPD. AECOPD have a high prevalence of OSAS. Overlap syndrome have significantly higher likelihood of obesity and metabolic syndrome compared to only COPD.

Cigarette smoke is a risk factor for severity and treatment outcome in patients with culture-positive tuberculosis

Objective

Smoking has been associated with tuberculosis (TB); however, the effects of smoking on the effectiveness of TB treatment remain unclear.

Materials and methods

Data were retrieved from case notes and interviews of subjects registered in the TB-reporting system from 2010 to 2012. Study cases were defined as subjects with TB-positive sputum cultures, whereas the controls were defined as subjects with non-TB-related pulmonary diseases. Statistical analyses included logistic regression and multivariate Cox proportional hazard regression models.

Results

A total of 245 cases with cultures positive for TB and 114 controls with non-TB-related pulmonary diseases and negative sputum cultures were recruited. Current smokers had the highest failure rate (33%) for TB treatment, and they had the most severe pulmonary lesions based on chest X-ray grading. Current smokers had a 1.36-fold (95% confidence interval 1.03–2.36, P<0.05) higher odds ratio for cultures positive for TB compared with nonsmokers. In subjects with TB-positive cultures, current smoking was associated with an increase in treatment days required for cultures to convert from positive to negative (hazard ratio 1.12, 95% confidence interval 1.03–1.39; P<0.05).

Conclusion

Longer periods of treatment may be required for TB patients who are current smokers.