Both pulmonary and extra-pulmonary factors predict the development of disability in chronic obstructive pulmonary disease

Health-related factors leading to disabilities in Korea: Survival analysis

The purpose of this study is to analyze (a) population and socioeconomic factors affecting disability, excluding the occurrence of disability due to accidents and congenital diseases, and (b) health-related behavioral factors and factors that can prevent and reduce the cause of disability due to disease in Korea. This study was a longitudinal research. Data were obtained from The 2018 Korean Health Panel (KHP) is a survey jointly conducted by the Korea Institute of Health and Social Affairs and the National Health Insurance Service. A total of 7, 372 (Mage = 52.14, SD = 21.39; Male = 47.52%) were analyzed in this study. People with Higher education attainments and more income levels were associated with lower hazard of developing new disabilities (all p < 0.05). In this study, the health factors that could be related to the occurrence of new disabilities were smoking, alcohol consumption, physical activity, and stress (all p < 0.0001). However, physical activity was negatively associated with the risk of developing a disability at all follow-ups (p < 0.05). Higher scores on the number of chronic diseases (valid scores = 0, 1, 2, 3, or more) represented a greater level of newly developing disability present at all follow-ups (all p < 0.0001). This longitudinal study confirmed the relationship between health-related factors and specific chronic diseases. Its findings can be used as a crucial foundation for establishing healthcare policies and services that can lower and prevent disability by preventing and reducing specific negative health behaviors and unhealthy behavioral factors, and alleviating chronic diseases in Korea.

Autophagy Induced by BCL2-Related ceRNA Network Participates in the Occurrence of COPD

Purpose

Chronic obstructive pulmonary disease (COPD) is a predominant cause of mortality worldwide. Autophagy, which depends on a lysosomal degradation pathway, plays an essential role in the occurrence of COPD. The aim of our study was to identify the potential function of autophagy and construct a BCL2-related competing endogenous RNA (ceRNA) network that induces autophagy in COPD.

Methods

Blood sample data from GSE31568, GSE24709, and GSE61741 were collected from the Gene Expression Omnibus (GEO) database. Differentially expressed miRNAs in COPD and controls were identified via GEO2R. Transcription factors were obtained from FunRich. DIANA, miRDB, miRTarBase, and TargetScan were used to predict target genes of miRNAs. Autophagy genes were collected from the Human Autophagy Database (HADb). The GSE151052 dataset was used to identify autophagy-related differentially expressed genes in tissues. Functional enrichment and protein–protein interaction (PPI) network analyses were conducted via Metascape and the STRING network. Spearman correlation analysis was used to analyze the relationship between autophagy-related differentially expressed genes and lung function. The BCL2-related ceRNA network was modeled by Cytoscape.

Results

We obtained 41 differentially expressed miRNAs and 10 significantly different transcription factors. We identified 19 autophagy-related differentially expressed genes that were significantly different (P<0.05) in tissue samples. The most significant enrichment in Metascape was an autophagy item, which further confirmed autophagy participation in the occurrence of COPD. PPI network analysis found four genes (BCL2, BECN1, MAPK8, and ITPR1), among which BCL2 was correlated with both FEV1/FVC and FEV1 prediction. Finally, the BCL2-related ceRNA network was constructed to clarify the interaction of RNAs and occurrence of autophagy, including 18 miRNAs and 65 lncRNAs.

Conclusion

We identified 19 autophagy-related differentially expressed genes that participated in COPD; among them, BCL2 was correlated with lung function, and a BCL2-related ceRNA network was constructed, which further revealed the potential mechanism of autophagy involvement in COPD.

Agreement between Cardiopulmonary Exercise Test and Modified 6-Min Walk Test in Determining Oxygen Uptake in COPD Patients with Different Severity Stages

BACKGROUND

In moderate-to-severe chronic obstructive pulmonary disease (COPD) patients the 6-min walk test (6MWT) is often exhaustive and correlates with the incremental cycle cardiopulmonary exercise test (CPET).

OBJECTIVES

The aim of this study was to assess the agreement between oxygen uptake (VO2) measured during the 6MWT by portable equipment and incremental cycle exercise in COPD patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) I-IV.

METHODS

A total of 30 patients with COPD GOLD I-IV (14 patients GOLD stage I and II and 16 patients GOLD stage III and IV) underwent a 6MWT and an incremental CPET. Breath-by-breath analysis for VO2, carbon dioxide output (VCO2), and minute ventilation (VE) were measured during each test. Blood gas analysis and lactate measurements were performed before, during, and after the test.

RESULTS

VO2 in COPD patients GOLD stage I and II was 16.2 ± 4.2 mL/kg/min measured by 6MWT and 20.5 ± 7.0 mL/kg/min measured by CPET as compared to GOLD stage III and IV (11.2 ± 3.7 mL/kg/min measured by 6MWT and 15.5 ± 4.3 mL/kg/min measured by CPET). No significant correlation in VO2 measurements could be found between both tests in COPD GOLD I and II (r = 0.17), whereas the VO2 significantly correlated in patients with COPD stage III and IV (r = 0.7).

CONCLUSIONS

A significant relationship between VO2 measured by 6MWT and CPET could only be found in patients with more severe COPD but not in milder stages. 6MWT and CPET provide different VO2 measurements in COPD patients. The two methods cannot be used interchangeably.

Evaluation of Skeletal Muscle Function in Lung Transplant Candidates

BACKGROUND

Lung transplantation (LTx) is offered to older and more complex patients who may be at higher risk of skeletal muscle dysfunction, but the clinical implications of this remain uncertain. The study aims were to characterize deficits in skeletal muscle mass, strength and physical performance, and examine the associations of these deficits with clinical outcomes.

METHODS

Fifty LTx candidates (58% men; age, 59 ± 9 years) were prospectively evaluated for skeletal muscle deficits: muscle mass using bioelectrical impedance, quadriceps, respiratory muscle and handgrip strength, and physical performance with the Short Physical Performance Battery. Comparisons between number of muscle deficits (low muscle mass, quadriceps strength and physical performance) and 6-minute walk distance (6MWD), London Chest Activity of Daily Living Questionnaire, and quality of life were assessed using one-way analysis of variance. Associations with pretransplant and posttransplant delisting/mortality, hospital duration, and 3-month posttransplant 6MWD were evaluated using Fisher exact test and Spearman correlation.

RESULTS

Deficits in quadriceps strength (n = 27) and physical performance (n = 24) were more common than muscle mass (n = 8). LTx candidates with 2 or 3 muscle deficits (42%) compared with those without any deficits (26%) had worse 6MWD = -109 m (95% confidence interval [CI], -175 to -43), London Chest Activity of Daily Living Questionnaire = 18 (95% CI, 7-30), and St. George's Activity Domain = 12 (95% CI, 2-21). Number of muscle deficits was associated with posttransplant hospital stay (r = 0.34, P = 0.04), but not with delisting/mortality or posttransplant 6MWD.

CONCLUSIONS

Deficits in quadriceps muscle strength and physical performance are common in LTx candidates and further research is needed to assess whether modifying muscle function pretransplant can lead to improved clinical outcomes.

Chronic obstructive pulmonary disease, cognitive impairment, and development of disability: the health and retirement study

RATIONALE

The relationship between chronic obstructive pulmonary disease (COPD) and cognitive impairment in leading to disability has not been characterized.

OBJECTIVES

We aimed to investigate the prevalence and cumulative incidence of disability among adults with and without COPD and the association of COPD and cognitive impairment with disability.

METHODS

We analyzed 2006-2008 waves of the Health and Retirement Study, a nationally representative longitudinal health survey. COPD was self-reported. Prevalent disability was defined as baseline dependency in one or more activities of daily living (ADLs) and incident disability as one or more additional ADL dependencies. We used a validated performance-based measure of cognition to identify dementia and mild cognitive impairment. Covariates included seven chronic diseases, four geriatric syndromes, and sociodemographics. We used logistic regression to test associations between COPD, cognitive status, and prevalent/incident disability.

MEASUREMENTS AND MAIN RESULTS

Of 17,535 participants at least 53 years of age in wave 2006 (representing 77.7 million Americans), 9.5% reported COPD and 13.5% mild cognitive impairment; 17.5% of those with COPD had mild cognitive impairment. Prevalent disability for COPD was 12.8% (5.2% for no-COPD, P < 0.001). An additional 9.2% with COPD developed incident disability at 2 years (4.0% for no-COPD, P < 0.001). In adjusted models, COPD was associated with baseline (odds ratio, 2.0) and incident disability (odds ratio, 2.1; adjusted for baseline disability). Cognitive impairment had an additive effect to COPD. The COPD-disability association, prevalent/incident, was of similar or greater magnitude than that of other chronic diseases (e.g., stroke, diabetes). The associations were maintained in sensitivity analyses using alternative definitions of disability (dependency in two or more ADLs, dependency in instrumental ADLs), and in analysis excluding respondents with dementia.

CONCLUSIONS

Both COPD and mild cognitive impairment increase the risk of disability. The risk conferred by COPD is significant and similar or higher than other chronic diseases.

A prospective multicentric study of pulmonary rehabilitation in patients with chronic obstructive pulmonary disease and different clinical phenotypes

BACKGROUND

Recently, it has been proposed that different clinical phenotypes can be recognized in patients with chronic obstructive disease (COPD), namely predominant airway disease or parenchymal destructive changes.

OBJECTIVES

The aim of this prospective multicenter study was to evaluate whether these two phenotypes may influence outcomes following a pulmonary rehabilitation program (PRP).

METHODS

We have prospectively evaluated 364 consecutive COPD patients (70 ± 8 years, 76.3% males) admitted to a standard hospital-based PRP in 6 Italian centers. According to their phenotype, the study cohort was divided into two groups: patients with airway obstructive (group 1, n = 208) or parenchymal destructive COPD (group 2, n = 156). Before and after PRP, values of 6-min walking distance, perceived breathlessness (Medical Research Council), health-related quality of life (St. George's Respiratory Questionnaire) and respiratory muscle function (maximal inspiratory and expiratory pressure) were recorded.

RESULTS

PRP resulted in significant improvements in all outcome measures without any significant differences between groups.

CONCLUSIONS

Our study confirms that COPD patients may benefit from pulmonary rehabilitation independent of their clinical phenotype.

Disability and recovery of independent function in obstructive lung disease: the cardiovascular health study

BACKGROUND

Chronic obstructive lung disease frequently leads to disability. Older patients may experience transitions between states of disability and independence over time.

OBJECTIVE

To identify factors associated with transition between states of disability and independent function in obstructive lung disease.

METHODS

We analyzed data on 4,394 participants in the Cardiovascular Health Study who completed prebronchodilator spirometry. We calculated the 1-year probability of developing and resolving impairment in ≥1 instrumental activity of daily living (IADL) or ≥1 activity of daily living (ADL) using transition probability analysis. We identified factors associated with resolving disability using relative risk (RR) regression.

RESULTS

The prevalence of IADL impairment was higher with moderate (23.9%) and severe (36.9%) airflow obstruction compared to normal spirometry (22.5%; p < 0.001). Among participants with severe airflow obstruction, 23.5% recovered independence in IADLs and 40.5% recovered independence in ADLs. In the adjusted analyses, airflow obstruction predicted the development of IADL, but not ADL impairment. Participants with severe airflow obstruction were less likely to resolve IADL impairment [RR 0.67 and 95% confidence interval (CI) 0.49-0.94]. Compared to the most active individuals (i.e. who walked ≥28 blocks per week), walking less was associated with a decreased likelihood of resolving IADL impairment (7-27 blocks: RR 0.81 and 95% CI 0.69-0.86 and <7 blocks: RR 0.73 and 95% CI 0.61-0.86). Increased strength (RR 1.16 and 95% CI 1.05-1.29) was associated with resolving IADL impairment.

CONCLUSIONS

Disability is common in older people, especially in those with severe airflow obstruction. Increased physical activity and muscle strength are associated with recovery. Research is needed on interventions to improve these factors among patients with obstructive lung disease and disability.

Development and validation of a lung transplant-specific disability questionnaire

BACKGROUND

Lung transplant (LT) aims to extend survival and improve patient-centred outcomes (PCOs) by reducing disability and improving health-related quality of life (HRQL). Few PCO instruments have been validated in LT populations. We aimed to develop and validate a shortened version of the valued life activities (VLA) disability scale specific to LT.

METHODS

We used data from 140 subjects participating in an ongoing cohort study of LT. Subjects completed a survey battery, including VLA items, and physical assessments before LT. To develop a shortened LT-specific VLA (LT-VLA), we iteratively deleted items from a longer 32-item VLA battery, retaining the instrument's conceptual framework, scoring and performance characteristics. We evaluated LT-VLA validity by testing correlations with a HRQL measure (Short Form-12 Physical Function (SF-12 PF) subscale), forced vital capacity % (FVC%) predicted and 6 minute walk distance (6MWD). Responsiveness was evaluated in 84 subjects who completed assessments before and after LT.

RESULTS

The 15-item LT-VLA scoring closely matched the longer VLA (correlations ≥0.96) and had excellent internal consistency (Cronbach's α 0.92). The LT-VLA required only 3 min or less to administer. The LT-VLA, measured as mean difficulty in performing each of the 15 activities queried, correlated with FVC% predicted (r=-0.30), 6MWD (r=-0.38) and SF-12 PF (r=-0.47) (all p<0.01). The LT-VLA mean difficulty was responsive to change from before to after LT (63% improvement; effect size=1.60).

CONCLUSIONS

The LT-VLA is a short, easy to administer, valid and responsive disease-specific PCO instrument that may be useful in clinical and research applications for lung transplantation.