Sleep-disordered breathing in patients with COPD and mild hypoxemia: prevalence and predictive variables

The benefits and drawbacks of home oxygen therapy for COPD: what's next?

INTRODUCTION

Home oxygen therapy is one of the few interventions that can improve survival in patients with chronic obstructive pulmonary disease (COPD) when administered appropriately, although it may cause side effects and be an unnecessary burden for some patients.

AREAS COVERED

This narrative review summarizes the current literature on the assessment of hypoxemia, different types of home oxygen therapy, potential beneficial and adverse effects, and emerging research on home oxygen therapy in COPD. A literature search was performed using MEDLINE and EMBASE up to January 2024, with additional articles being identified through clinical guidelines.

EXPERT OPINION

Hypoxemia is common in patients with more severe COPD. Long-term oxygen therapy is established to prolong survival in patients with chronic severe resting hypoxemia. Conversely, in the absence of chronic severe resting hypoxemia, home oxygen therapy has an unclear or conflicting evidence base, including for palliation of breathlessness, and is generally not recommended. However, beneficial effects in some patients cannot be precluded. Evidence is emerging on the optimal daily duration of oxygen use, the role of high-flow and auto-titrated oxygen therapy, improved informed decision-making, and telemonitoring. Further research is needed to validate novel oxygen delivery systems and monitoring tools and establish long-term effects of ambulatory oxygen therapy in COPD.

Prevalence and clinical characteristics of sleep disorders in chronic obstructive pulmonary disease: A systematic review and meta-analysis

BACKGROUND

Sleep disorders, including obstructive sleep apnea (OSA), restless leg syndrome (RLS) and insomnia, are present in chronic obstructive pulmonary disease (COPD) with varied prevalence. The aim of this systematic review and meta-analysis was to investigate prevalence of OSA, RLS and insomnia in patients with COPD and summarize their clinical characteristics.

METHODS

We searched PubMed, Web of Science and Scopus for eligible articles reporting the prevalence of OSA, RLS, and insomnia in COPD patients. The Newcastle‒Ottawa scale was applied for quality assessment. Odds ratios or mean differences with 95 % confidence intervals (CIs) were applied for the overall prevalence calculation and clinical characteristics assessment. Sensitivity analysis, subgroup analysis and meta-regression were conducted to evaluate the heterogeneity of the results.

RESULTS

Sixty articles reporting the prevalence of sleep disorders in patients with COPD were included, and the prevalence of OSA, RLS, and insomnia reached 29.1 %(95%CI 27.2%-30.9 %), 21.6 %(95%CI 11.8%-33.3 %) and 29.5 %(95%CI 16.9%-44.0 %), respectively. COPD patients with OSA were characterized by male sex (OR 1.631 95 % CI: 1.231-2.161), obesity(kg/m2) (MD 4.435, 95 % CI 3.218-5.652), higher Epworth Sleepiness Scale (MD: 3.741, 95 % CI: 0.655-6.828, p = 0.018), better pulmonary function (MD 5.66, 95 % CI 3.546-7.774) and higher risks of hypertension (OR 1.933 95 % CI 1.382-2.70) and diabetes (OR 1.898 95 % CI 1.264-2.849). COPD patients with RLS were associated with a higher Epworth sleepiness scale (ESS) score (MD 3.444, 95 % CI 1.880-5.008) and a longer COPD duration(year) (MD: 3.656, 95 % CI: 2.209-5.103). COPD patients with insomnia were characterized by female sex(OR 0.556, 95%CI 0.545,0.567, p < 0.001).

CONCLUSION

Our study suggests that OSA, RLS and insomnia are common in COPD patients with specific clinical characteristics. Further studies are needed to explore the interactions between COPD and sleep disorders.

Diabetic retinopathy is a predictor of chronic respiratory failure: A nationwide register-based cohort study

Purpose

Diabetic retinopathy (DR) is a hypoxic retinal disease, but so far, the association with systemic hypoxia is poorly understood. Hence, the aim of this study was to evaluate cross-sectional and longitudinal associations between DR and chronic respiratory failure (CRF) in a national cohort.

Design

Cross-sectional and 5-year longitudinal register-based cohort study.

Methods

Between 2013 and 2018, we included patients with diabetes from the Danish Registry of Diabetic Retinopathy, who were each age and sex matched with five controls without diabetes. At index date, the prevalence of CRF was compared between cases and controls, and the longitudinal relationship between DR and CRF was assessed in a five-year follow-up.

Results

At baseline, we identified 1,980 and 9,990 patients with CRF among 205,970 cases and 1,003,170 controls. The prevalence of CRF was higher among cases than controls (OR 1.75, 95% CI 1.65-1.86), but no difference between cases with and without DR was found.During follow-up, we identified 1,726 and 5,177 events of CRF among cases and controls, respectively. The incidence of CRF was higher among both cases with and without DR compared to controls (DR level 0: HR 1.24, 95% CI 1.16-1.33, DR level 1-4: HR 1.86, 95% CI 1.63-2.12), and higher among cases with DR compared to cases without DR (HR 1.54, 95% CI 1.38-1.72).

Conclusion

In this study based on nationwide data, we found an increased risk of present and incident CRF in patients with diabetes with or without DR, and we identified DR as a predictor of future CRF.

The impact of impaired sleep quality on symptom change and future exacerbation of chronic obstructive pulmonary disease

Purpose

Study the impact of impaired sleep quality on symptom change and future exacerbation of chronic obstructive pulmonary disease (COPD) patients.

Methods

This was a prospective study. Patients with COPD were recruited into the study and followed up for one year. Pittsburgh sleep quality index (PSQI) was collected at baseline. Symptom change was assessed with Minimum clinically important difference (MCID) in COPD Assessment Test (CAT) at 6-month visit, which is an indicator to assess symptom improvement. Exacerbation was recorded during the one-year visit. PSQI score > 5 was defined as poor sleep quality, whereas PSQI score ≤ 5 was defined as good sleep quality. MCID was defined as attaining a CAT decrease ≥ 2.

Results

A total of 461 patients were enrolled for final analysis. Two hundred twenty-eight (49.4%) patients had poor sleep quality. Overall, 224 (48.6%) patients attained MCID at 6-month visit and the incidence of exacerbation during the one-year visit was 39.3%. Fewer patients with impaired sleep quality achieved MCID than patients with good sleep quality. Good sleepers were significantly more likely to attain MCID (OR: 3.112, p < 0.001) than poor sleepers. Fewer poor sleepers in GOLD A and D groups attained MCID with ICS/LABA, and fewer poor sleepers in the GOLD D group attained MCID with ICS/LABA/LAMA than good sleepers. Poor sleep quality was a greater risk factor of future exacerbation in Cox regression analysis. The ROC curves showed that PSQI score had a predictive capacity for future exacerbation. More patients with poor sleep quality experienced future exacerbation in GOLD B and D group with treatment of ICS/LABA/LAMA compared to good sleepers.

Conclusions

COPD patients with impaired sleep quality were less likely to achieve symptom improvement and were at increased risk of future exacerbation compared to patients with good sleep quality. Besides, sleep disturbance may affect the symptom improvement and future exacerbation of patients with different inhaled medication or in different GOLD groups.

Sleep quality in COPD patients: correlation with disease severity and health status

Objective:

To evaluate clinical predictors of poor sleep quality in COPD patients with and without obstructive sleep apnea (OSA).

Methods:

Consecutive stable patients with COPD were evaluated for OSA by means of overnight polysomnography; for sleep quality by means of the Pittsburgh Sleep Quality Index (PSQI); and for disease impact by means of the COPD Assessment Test. COPD severity was graded in accordance with the 2020 GOLD guidelines. Predictors of poor sleep quality were evaluated by multivariate logistic regression analysis.

Results:

We studied 51 patients with COPD alone and 51 patients with COPD and OSA. Both groups had similar age (66.2 ± 9.2 years vs. 69.6 ± 10.7, p = 0.09) and airflow limitation (p = 0.37). Poor sleep quality was present in 74.8% of the study participants, with no significant difference between COPD patients with and without OSA regarding PSQI scores (p = 0.73). Polysomnography showed increased stage 1 non-rapid eye movement sleep and arousal index, as well as reduced sleep efficiency and stage 3 non-rapid eye movement sleep, in the group of patients with COPD and OSA (p < 0.05). Independent predictors of poor sleep quality were GOLD grade C/D COPD (OR = 6.4; 95% CI, 1.79-23.3; p < 0.01), a COPD Assessment Test score ≥ 10 (OR = 12.3; 95% CI, 4.1-36.5; p < 0.01), and lowest SaO₂ < 80% (p < 0.0001).

Conclusions:

Poor sleep quality is quite common in patients with COPD and is associated with severe COPD and poor health status, having a negative impact on overall quality of life. Despite changes in polysomnography, OSA appears to have no impact on subjective sleep quality in COPD patients.

The risk of cardiovascular and cerebrovascular disease in overlap syndrome: a meta-analysis

STUDY OBJECTIVES

To undertake a meta-analysis of literature comparing the prevalence of cardiovascular and cerebrovascular comorbidities between patients with overlap syndrome (OS) and patients with chronic obstructive pulmonary disease (COPD) or patients with obstructive sleep apnea.

METHODS

Studies about the cardiovascular and cerebrovascular disease of OS were searched for among several electronic databases from the time of database construction to June 2019. Two independent reviewers performed the process of study screening, quality assessment, and data extraction. Meta-analysis of odds ratios (ORs) was carried out by RevMan5.3 under either fixed-effects or random-effects models. Sensitivity analysis was conducted to examine the robustness of pooled outcome.

RESULTS

A total of 17 articles were included. Compared with COPD/obstructive sleep apnea, OS significantly increased the risk of developing hypertension (OS vs COPD: OR = 1.94, 95% confidence interval [CI] [1.49, 2.52]; OS vs obstructive sleep apnea: OR = 2.05, 95% CI [1.57, 2.68]) and pulmonary hypertension (OS vs COPD: OR = 2.96, 95% CI [1.30, 6.77]; OS vs obstructive sleep apnea: OR = 5.93, 95% CI [1.84, 18.42]). There was no significant difference in the prevalence of coronary heart disease (OR = 1.19, 95% CI [.67,2.11]) and cerebrovascular disease (OR = 2.43, 95% CI [0.81, 7.31]) between patients with COPD and patients with OS. However, the sensitivity analysis showed that the pooled outcome of the comparison of pulmonary arterial pressure between patients with OS and patients with COPD was not stable.

CONCLUSIONS

OS significantly increased cardiovascular risk including the prevalence of hypertension and pulmonary hypertension. However, since the pooled outcome about pulmonary arterial pressure was not stable, further studies are still required.

Patterns of brain structural alteration in COPD with different levels of pulmonary function impairment and its association with cognitive deficits

Background

To explore patterns of brain structural alteration in chronic obstructive pulmonary disease (COPD) patients with different levels of lung function impairment and the associations of those patterns with cognitive functional deficits using voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analyses based on high-resolution structural MRI and diffusion tensor imaging (DTI).

Methods

A total of 115 right-handed participants (26 severe, 29 moderate, and 29 mild COPD patients and a comparison group of 31 individuals without COPD) completed tests of cognitive (Montreal Cognitive Assessment [MoCA]) and pulmonary function (forced expiratory volume in 1 s [FEV1]) and underwent MRI scanning. VBM and TBSS analyses were used to identify changes in grey matter density (GMD) and white matter (WM) integrity in COPD patients. In addition, correlation analyses between these imaging parameter changes and cognitive and pulmonary functional impairments were performed.

Results

There was no significant difference in brain structure between the comparison groups and the mild COPD patients. Patients with moderate COPD had atrophy of the left middle frontal gyrus and right opercular part/triangular part of the inferior frontal gyrus, and WM changes were present mainly in the superior and posterior corona radiata, corpus callosum and cingulum. Patients with severe COPD exhibited the most extensive changes in GMD and WM. Some grey matter (GM) and WM changes were correlated with MoCA scores and FEV1.

Conclusions

These findings suggest that patients with COPD exhibit progressive structural impairments in both the GM and the WM, along with impaired levels of lung function, highlighting the importance of early clinical interventions.