Correlation of cardiopulmonary exercise testing parameters with quality of life in stable COPD patients

Interactions between Cognitive, Affective, and Respiratory Profiles in Chronic Respiratory Disorders: A Cluster Analysis Approach

This study conducted at Leamna Pulmonology Hospital investigated the interrelations among cognitive, affective, and respiratory variables within a cohort of 100 patients diagnosed with chronic respiratory conditions, utilizing sophisticated machine learning-based clustering techniques. Spanning from October 2022 to February 2023, hospitalized individuals confirmed to have asthma or COPD underwent extensive evaluations using standardized instruments such as the mMRC scale, the CAT test, and spirometry. Complementary cognitive and affective assessments were performed employing the MMSE, MoCA, and the Hamilton Anxiety and Depression Scale, furnishing a holistic view of patient health statuses. The analysis delineated three distinct clusters: Moderate Cognitive Respiratory, Severe Cognitive Respiratory, and Stable Cognitive Respiratory, each characterized by unique profiles that underscore the necessity for tailored therapeutic strategies. These clusters exhibited significant correlations between the severity of respiratory symptoms and their effects on cognitive and affective conditions. The results highlight the benefits of an integrated treatment approach for COPD and asthma, which is personalized based on the intricate patterns identified through clustering. Such a strategy promises to enhance the management of these diseases, potentially elevating the quality of life and everyday functionality of the patients. These findings advocate for treatment customization according to the specific interplays among cognitive, affective, and respiratory dimensions, presenting substantial prospects for clinical advancement and pioneering new avenues for research in the domain of chronic respiratory disease management.

Value of cardiopulmonary exercise testing in the assessment of symptoms and quality of life in Asian patients with chronic obstructive pulmonary disease

BACKGROUND

The natural course of chronic obstructive pulmonary disease (COPD) is characterized by symptom exacerbation and quality-of-life reduction. Therefore, symptoms should be properly assessed. Some studies have demonstrated a weak correlation between cardiopulmonary exercise testing (CPET) parameters and symptoms in patients with COPD; however, data on Asian patients are lacking. We investigated the value of CPET parameters in assessing symptoms and quality of life in Asian patients with COPD.

METHODS

Of 681 patients who underwent CPET at Asan Medical Center between January 2020 and June 2022, we analyzed 195 patients with COPD in this retrospective study. A cycle ergometer was used for the incremental protocol. The modified Medical Research Council (mMRC) dyspnea scale and COPD Assessment Test (CAT) were administered to assess the patients' symptoms.

RESULTS

The mMRC grade was related to maximal oxygen uptake (VO2 max, L/min) (Spearman's correlation coefficient ρ=-0.295, P<0.001) and physiological dead space/tidal volume ratio at peak exercise (VD/VT peak) (ρ=0.256, P<0.001). The CAT score was significantly correlated with VO2 max (L/min) (Spearman's correlation coefficient ρ=-0.297, P<0.001) and VD/VT peak (ρ=0.271, P<0.001), but had no correlation with breathing reserve (ρ=-0.122, P=0.089). The optimal cut-off values of VO2 max and VD/VT peak for predicting the onset of clinically significant dyspnea were 1.099 L/min and 0.295, respectively.

CONCLUSIONS

VO2 max and VD/VT peak comprehensively reflect the symptoms and health-related quality of life of patients with COPD.

Poor Work Efficiency is Associated with Poor Exercise Capacity and Health-Related Quality of Life in Patients with Chronic Obstructive Pulmonary Disease

Introduction

Chronic obstructive pulmonary disease (COPD) is a progressive disease with deteriorating cardiopulmonary function that decreases the health-related quality of life (HRQL) and exercise capacity. Patients with COPD often have cardiovascular and muscular problems that hinder oxygen uptake by peripheral tissues, resulting in poor oxygen consumption efficiency. It is important to develop new physiological parameters to evaluate oxygen consumption efficiency during activities and to evaluate its association with exercise capacity and HRQL. Work efficiency (WE) measures oxygen consumption efficiency during exercise. We hypothesize that patients with poor WE should have exercise intolerance and poor HRQL. Therefore, we aimed to evaluate the association between WE and exercise capacity, HRQL and other cardiopulmonary parameters.

Patients and Methods

Seventy-eight patients with COPD were evaluated with spirometry, cardiopulmonary exercise testing, and assessment of dyspnea score and HRQL (using the St. George’s Respiratory Questionnaire [SGRQ]). Cardiopulmonary exercise testing was performed using a cycle ergometer with an incremental protocol and exhaled breath analysis to assess oxygen consumption. WE was defined as the relationship between oxygen consumption and workload.

Results

There were 31 patients with normal WE (group I) and 47 patients (group II) with poor WE. Patients with poor WE had lower exercise capacity (maximal oxygen consumption, group I vs II as 1050±53 vs 845 ±34 mL/min, p=0.0011), poorer HRQL (SGRQ score 41.1±3.0 vs 55±2.2, p=0.0002), higher exertional dyspnea score (5.1±0.2 vs 6.1±0.2, p= 0.0034) and early anaerobic metabolism during exercise (anaerobic threshold, 672±27 vs 583 ±18 mL/min, p=0.0052).

Conclusion

WE is associated with exercise capacity and HRQL. Here, patients with poor WE also had exercise intolerance, poorer HRQL, and more exertional dyspnea.

Metronome-Paced Incremental Hyperventilation May Predict Exercise Tolerance and Dyspnea as a Surrogate for Dynamic Lung Hyperinflation During Exercise

Background

Dynamic lung hyperinflation (DLH) has been evaluated based on decreased inspiratory capacity (IC) during exercise load. However, this is not routinely done in clinical practice. We have developed a convenient method of metronome-paced incremental hyperventilation (MPIH) and reported its usefulness. In the present study, we compared these two methods for evaluating DLH and examined whether our MPIH method can be used to predict DLH during exercise.

Methods

DLH was measured by MPIH and constant load exercise (CLE) in 35 patients with stable COPD. DLH was defined as the most decreased IC (IC_lowest) and the most decreases in IC from IC at rest (-IC_lowest), and we compared between these two methods.

Results

The IC_lowest in CLE and the -IC_lowest in MPIH were significantly lower in emphysema-dominant COPD than in emphysema-nondominant COPD. Both IC_lowest and -IC_lowest showed significant correlations between the two methods (r = 0.67, p < 0.01 and r = 0.44, p < 0.01, respectively). The endurance time of CLE was significantly correlated with IC_lowest following MPIH (r = 0.62, p < 0.01) but not with that obtained by the CLE method. Furthermore, the IC_lowest of MPIH was more significantly correlated with endurance time in emphysema-dominant COPD. Weak but significant correlations between the -IC_lowest obtained by each method and maximum modified Borg scale were observed (MPIH: r = 0.38, p = 0.02; CLE: r = 0.37, p = 0.03).

Conclusion

The MPIH method may be a convenient method to predict exercise tolerance and dyspnea as a clinically useful synergic screening surrogate for DLH during exercise.

Comparison of Functional Capacity and Symptoms of COPD Patients with and without Pulmonary Hypertension

OBJECTIVE

Pulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD) associated with a decrease in the survival rate of patients with COPD. Our aim was to investigate whether PH impairs the functional capacity and symptoms in patients with COPD. In addition, we aimed to evaluate the correlation between the functional capacity and symptoms score in patients with COPD.

MATERIALS AND METHODS

This prospective cross-sectional study enrolled 64 patients with moderate to severe COPD, prospectively. All patients underwent the pulmonary function test, echocardiography, 6-minute walk test (6MWT), and cardiopulmonary exercise testing (CPET). We applied the modified Medical Research Council (mMRC) dyspnea scale and COPD Assessment Test (CAT) to all patients. The mean pulmonary arterial pressure (mPAP) >30 mmHg with echocardiography was considered as PH. The patients were grouped according to the presence of PH as COPD-PH (n=30) and COPD-nonPH (n=34).

RESULTS

Hospitalization rate was higher in the COPD-PH group than in the COPD-nonPH group (p=0.006). The 6MWT results were lower in the COPD-PH group compared to the COPD-nonPH group (325±61 m vs. 354±46 m, respectively, p=0.025). In the COPD-PH group, the maximum oxygen consumption (VO2max) was lower, but the difference did not reach statistical significance (p=0.118). Although the maximum load and minute ventilation were lower in the COPD-PH group, the end-tidal pressure of CO2 (PETCO2) was higher (p=0.033, p=0.036, and p=0.009, respectively). However, the CAT score and mMRC were similar between the groups (p=0.405 and p=0.238, respectively).

CONCLUSION

An elevated PAP in patients with COPD limits the exercise capacity. Using CPET in the functional evaluation of patients with COPD may be beneficial in the early detection of PH.

Impact Of Peak Oxygen Pulse On Patients With Chronic Obstructive Pulmonary Disease

Introduction

Patients with chronic obstructive pulmonary disease (COPD) are at an increased risk of cardiovascular comorbidities such as pulmonary hypertension or heart failure. Impaired cardiovascular function often has a significant impact on patients with COPD. Oxygen pulse (O₂P) is a surrogate for stroke volume. However, studies regarding O₂P, health-related quality of life (HRQL), and exercise capacity in patients with COPD are lacking. We aimed to confirm the association between O₂P, HRQL, exercise capacity, severe exacerbation of COPD, and other parameters in exercise testing.

Materials and methods

This study included 79 patients with COPD who underwent lung function testing, a cardiopulmonary exercise test (CPET), Borg Dyspnea Scale evaluation, completion of the St. George's Respiratory Questionnaire, and echocardiography. Cardiovascular comorbidities, COPD-related hospitalizations, and emergency room visits were recorded. We compared these parameters between two groups of patients: those with normal peak O₂P and those with impaired peak O₂P. The relationships of peak O₂P with CPET and lung function were analyzed using simple linear regression.

Results

Patients with normal peak O₂P had higher exercise capacity (peak oxygen uptake and work rate), better HRQL, lower dyspnea score, lower COPD-related hospitalizations, and higher circulatory and ventilator parameters than patients with impaired peak O₂P. According to a simple linear regression analysis, the anaerobic threshold (AT) and forced expiratory volume in one second (FEV1) showed a significant association with peak O₂P, and the Pearson correlation coefficients (Pearson's r) were 0.756 and 0.461, respectively.

Conclusion

Peak O₂P has a significant impact on exercise capacity, HRQL, dyspnea, COPD-related hospitalization, and circulatory and ventilatory functions in patients with COPD. The AT and FEV1 have strong and moderate associations with peak O₂P, respectively. Therefore, peak O₂P is an important indicator of disease severity for patients with COPD.

Validation of the St George's respiratory questionnaire and risks factors affecting the quality of life of Lebanese COPD and asthma patients

Objective: We aimed to validate the Arabic version of the St George's Respiratory Questionnaire (SGRQ) for use in Lebanese Chronic obstructive pulmonary disease (COPD) and asthma patients and to identify risk factors that might affect the quality of life in these patients. Methods: COPD (n = 90) and asthma patients (n = 124) were recruited from the outpatient clinics of the Pulmonology department of a university hospital and a medical center in Beirut. They filled out a standardized questionnaire. The total SGRQ score and the component scores (symptoms, activity and impacts) were calculated. To confirm the SGRQ validity in the Lebanese population, factor analyses were applied for the whole sample, only asthma and only COPD patients, respectively. The associations between the total SGRQ score and FEV₁% predicted, CCQ score and MRC scale were assessed. Multiple linear regression models were used to evaluate the association between the total SGRQ scores and the socio-demographics and the diseases risk factors. Results: COPD patients had a higher SGRQ total and subscales scores compared to asthma patients. A high Cronbach's alpha was found for the whole sample (0.802), only COPD patients (0.833) and only asthma patients (0.734). A significant negative correlation was found between FEV₁% predicted and the total SGRQ scores. Occupational exposure, BMI and previous waterpipe smoking were among the factors that significantly and positively influenced a higher SGRQ score. Conclusions: The Lebanese version of the SGRQ emerges as a good health-related quality of life evaluative instrument that is reasonable to be used in COPD and asthma patients in Lebanon.

Nitrogen single-breath washout test for evaluating exercise tolerance and quality of life in patients with chronic obstructive pulmonary disease

Pulmonary function tests (PFTs) traditionally used in clinical practice do not accurately predict exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to assess whether the nitrogen single-breath washout (N₂SBW) test explains exercise intolerance and poor quality of life in stable COPD patients. This cross-sectional study included 31 patients with COPD subjected to PFTs (including the N₂SBW test) and a cardiopulmonary exercise test (CPET). Patients were also evaluated using the following questionnaires: the COPD assessment test (CAT), the 36-Item Short Form Health Survey (SF36) and St. George's Respiratory Questionnaire (SGRQ). Peak oxygen uptake (peak VO₂) was negatively correlated with the phase III slope of the N₂SBW (SIII_N2) (r=-0.681, P<0.0001) and positively correlated with forced expiratory volume in one second (FEV₁; r=0.441, P=0.013). Breathing reserve was negatively correlated with SIII_N2, closing volume/vital capacity, and residual volume (RV) (r=-0.799, P<0.0001; r=-0.471, P=0.007; r=-0.401, P=0.025, respectively) and positively correlated with FEV₁, forced vital capacity (FVC) and FEV₁/FVC (r=0.721; P<0.0001; r=0.592, P=0.0004; r=0.670, P<0.0001, respectively). SIII_N2 and CAT were independently predictive of VO₂ and breathing reserve at peak exercise. RV, FVC, and FEV₁ were independently predictive of the SF36-physical component summary, SF36-mental component summary, and breathing reserve, respectively. The SGRQ did not present any independent variables that could explain the model. In stable COPD patients, inhomogeneity of ventilation explains a large degree of exercise intolerance assessed by CPETs and, to a lesser extent, poor quality of life.

Early-Phase Recovery of Cardiorespiratory Measurements after Maximal Cardiopulmonary Exercise Testing in Patients with Chronic Obstructive Pulmonary Disease

Background. This study investigated respiratory gas exchanges and heart rate (HR) kinetics during early-phase recovery after a maximal cardiopulmonary exercise test (CPET) in patients with chronic obstructive pulmonary disease (COPD) grouped according to airflow limitation. Methods. Thirty control individuals (control group: CG) and 81 COPD patients (45 with "mild" or "moderate" airflow limitation, COPD_I-II, versus 36 with "severe" or "very severe" COPD, COPD_III-IV) performed a maximal CPET. The first 3 min of recovery kinetics was investigated for oxygen uptake ([Formula: see text]O₂), minute ventilation ([Formula: see text]), respiratory equivalence, and HR. The time for [Formula: see text]O₂ to reach 25% (T_1/4[Formula: see text]O₂) of peak value was also determined and compared. Results. The [Formula: see text]O₂, [Formula: see text], and HR recovery kinetics were significantly slower in both COPD groups than CG (p < 0.05). Moreover, COPD_III-IV group had significantly higher [Formula: see text]O₂ and [Formula: see text] during recovery than COPD_I-II group (p < 0.05). T_1/4[Formula: see text]O₂ significantly differed between groups (p < 0.01; 58 ± 18 s in CG, 79 ± 26 s in COPD_I-II group, and 121 ± 34 s in COPD_III-IV) and was significantly correlated with forced expiratory volume in one second in COPD patients (p < 0.001, r = 0.53) and with peak power output (p < 0.001, r = 0.59). Conclusion. The COPD groups showed slower kinetics in the early recovery period than CG, and the kinetics varied with severity of airflow obstruction.