Risk Factors of Poor Outcomes after Admission for a COPD Exacerbation: Multivariate Logistic Predictive Models

The role of serum chloride ion in the prognosis of COPD

BACKGROUND

As exacerbations of chronic obstructive pulmonary disease (COPD) are one of the leading causes of hospitalization and are associated with significant mortality, it is particularly important to accurately assess the risk of exacerbations in COPD. Most of the current clinical biomarkers are related to inflammation and few consider how ion levels affect COPD. Chloride ion, the second most abundant serum electrolyte, has been shown to be associated with poor prognoses in several diseases, but their relationship with COPD remains unclear.

METHODS

In total, 105 patients with acute exacerbations of COPD were recruited. Data on clinical characteristics, lung function, blood count, blood biochemistry, relevant scales including the Clinical COPD Questionnaire (CCQ), BODE (BMI, airflow obstruction, dyspnea, exercise capacity) index and the St. George's Respiratory Questionnaire (SGRQ) were collected from all patients for statistical analysis.

RESULT

There were significant differences in lung function indicators and disease severity in the low chloride ion subgroup compared with the high chloride ion subgroup. On multiple logistic regression analysis, chloride ion was an independent factor affecting lung function in COPD patients (OR=0.808, 95% CI: 0.708 - 0.922, p=0.002). The sensitivity of chloride ion in predicting COPD severity was 78%, the specificity was 63%, and the area under the curve was 0.734 (p<0.001). Subgroup analysis showed that chloride ion was a stronger predictor in male and smoking patients.

CONCLUSIONS

Chloride ion was a novel prognostic biomarker for COPD, and low levels of chloride ion were independently associated with exacerbations in COPD patients.

Factors influencing nasal airway pressure and comfort in high-flow nasal cannula oxygen therapy: a volunteer study

BACKGROUND

High-flow nasal cannula (HFNC) oxygen therapy is essentially a constant-flow, noninvasive respiratory support system similar to a noninvasive ventilator operating in constant-flow mode. The clinical outcome of HFNC oxygen therapy is strongly associated with the pressure generated by high-flow gas and the patient's comfort level. This study was performed to explore the relevant factors affecting pressure and comfort of HFNC oxygen therapy in vivo.

METHODS

Thirty-five healthy volunteers were enrolled in the trial. They underwent placement of nasal cannulas of various inner diameters (3, 4 or 5 mm) and treatment with different HFNC devices [HFT-300 (Weishengkang Medical Technology Co., Ltd., Jiangsu China) or H-80 M (BMC Medical Co., Ltd., Beijing China)],and the nasal airway pressure and comfort were assessed. Multiple linear regression was used to determine predictors of airway pressure.

RESULTS

Multiple linear regression showed that the end-expiratory pressure was associated with the flow rate, sex, height, and cannula size. The end-expiratory pressure increased by 0.6 cmH2O per 1-mm increase in cannula diameter, decreased by 0.3 cmH2O per 10-cm increase in participant height (with a 0.35 cmH2O decrease for men), and increased by 1 cmH2O when the flow rate increased by 10 L/min (R2 = 0.75, P < 0.05 for all variables in model). In addition, the pressure generated by the H-80 M device was higher than that generated by the HFT-300 device (P < 0.05). Discomfort manifested as difficulty in expiration, and its severity increased as the cannula diameter increased; however there was no significant difference in comfort between the two HFNC devices (P > 0.05).

CONCLUSION

In volunteers undergoing HFNC oxygen therapy, the nasal cannula diameter, flow rate, sex, height, and device model can affect the nasal airway pressure, and the nasal catheter diameter and flow rate can affect comfort. These factors should be given close attention in clinical practice.

TRIAL REGISTRATION

ChiCTR2300068313 (date of first registration: 14 February 2023,  https://www.chictr.org.cn ).

Relationship of Red Cell Index with the Severity of Chronic Obstructive Pulmonary Disease

Background

We aimed to investigate the association between red cell index (RCI) and the severity of Chronic Obstructive Pulmonary Disease (COPD), and compare predictive value of RCI, neutrophil–lymphocyte ratio (NLR) and platelet–lymphocyte ratio (PLR) for the severity of COPD.

Methods

A total of 207 participants were recruited (100 COPD patients and 107 healthy controls). COPD patients were divided into two groups according to the optimal cut-off value of RCI determined by the receiver operating characteristic (ROC) curve. Pearson’s correlation test, logistic regression analysis and other tests were performed.

Results

Compared with low RCI group, the forced expiration volume in 1 second (FEV₁) and FEV₁ in percent of the predicted value (FEV₁%) in high RCI group were lower (p = 0.016, p = 0.001). There was a negative correlation between RCI and FEV₁% (r = −0.302, p = 0.004), while no correlation between FEV₁% and NLR as well as PLR were found. RCI showed higher predictive value than NLR and PLR for predicting Global Initiative for Chronic Obstructive Lung Disease classification (GOLD), with a cut-off value of 1.75 and area under the curve (AUC) of 0.729 (p = 0.001). Multivariate logistic regression analysis proved that RCI was an independent factor for lung function in COPD patients (odds ratio [OR] = 4.27, 95% CI: 1.57–11.63, p = 0.004).

Conclusion

RCI is a novel biomarker that can better assess pulmonary function and severity of COPD than NLR and PLR. Higher RCI is related to deterioration of pulmonary function.

Association Between Routine Blood Biomarkers and Clinical Phenotypes and Exacerbations in Chronic Obstructive Pulmonary Disease

Introduction

Chronic obstructive pulmonary disease (COPD) is associated with increased lung and systemic inflammation. We aimed to identify associations between easy-to-obtain blood biomarkers and the frequency and severity of exacerbations.

Methods

Cross-sectional, multicentre study performed in four centres in Spain, Italy, Bulgaria, and Slovenia. Blood samples were obtained for blood cell count, C-reactive protein (CRP), alpha-1 antitrypsin (AAT) and fibrinogen analysis. The neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and eosinophil/basophil ratio (EBR) were calculated. Firstly, patients were divided into clinical phenotypes according to the Spanish guidelines of COPD, and secondly, patients were classified into 2 groups: non-exacerbators (≤1 ambulatory exacerbation in the previous year) and exacerbators (≥2 ambulatory exacerbations or 1 hospitalisation in the previous year). A multivariate stepwise logistic regression model was performed to identify laboratory parameters associated with exacerbators.

Results

A total of 355 patients with a mean age 66 years (SD=8.9) were included, and 64% were male. The mean FEV1% (forced expiratory volume in the first second) was 55% (SD=20%), and the mean COPD Assessment Test (CAT) score was 15.6 (SD=7.9). One hundred ninety-six (55.2%) patients were classified in the non-exacerbator group, and 159 (44.8%) were exacerbators. Patients in the exacerbators group presented lower haemoglobin levels (p=0.019) and ERB (p= 0.023) but higher CRP levels (p=0.001). In the multivariate analysis, females, higher levels of CRP, lower FEV1% and low EBR were independently related to exacerbators.

Conclusion

Female sex, having a more severe impairment of lung function, higher CRP levels and a lower EBR are associated with an exacerbator phenotype in COPD.

Determinants of Response to Roflumilast in Severe Chronic Obstructive Pulmonary Disease. Pooled Analysis of Two Randomized Trials

RATIONALE

Roflumilast reduces exacerbations in patients with severe chronic obstructive pulmonary disease associated with chronic bronchitis and a history of exacerbations. Further characterization of patients most likely to benefit is warranted.

OBJECTIVES

Define characteristics that most robustly identify patients who derive greatest exacerbation risk reduction with roflumilast.

METHODS

Predefined, pooled analyses of REACT (Roflumilast in the Prevention of COPD Exacerbations While Taking Appropriate Combination Treatment; NCT01329029) and RE²SPOND (Roflumilast Effect on Exacerbations in Patients on Dual [LABA/ICS] Therapy; NCT01443845) multicenter, randomized, double-blind, placebo-controlled studies. The primary endpoint was rate of moderate or severe exacerbations per patient per year.

MEASUREMENTS AND MAIN RESULTS

In the overall intention-to-treat population (n = 4,287), roflumilast reduced moderate or severe exacerbations by 12.3% (rate ratio, 0.88, 95% confidence interval, 0.80-0.97; P = 0.0086) and severe exacerbations by 16.1% (0.84; 0.71-0.99; P = 0.0409) versus placebo. The reduction in moderate or severe exacerbations with roflumilast was most pronounced in patients who had been hospitalized for an exacerbation in the prior year (0.74; 0.63-0.88; P = 0.0005); had more than two exacerbations in the prior year (0.79; 0.65-0.96; P = 0.0160); or had baseline eosinophils ≥150 cells/μl (0.81; 0.71-0.93; P = 0.0020), ≥150 to <300 cells/μl (0.84; 0.71-0.98; P = 0.0282), or ≥300 cells/μl (0.77; 0.61-0.97; P = 0.0264). Similar subgroup results were noted for severe exacerbations. In patients with prior hospitalization and higher baseline blood eosinophil concentrations, roflumilast reduced moderate or severe exacerbations by 34.5% at ≥150 cells/μl (0.65; 0.52-0.82; P = 0.0003) and 42.7% at ≥300 cells/μl (0.57; 0.37-0.88; P = 0.0111) versus placebo.

CONCLUSIONS

This prespecified, pooled analysis confirms the benefit of roflumilast in decreasing exacerbations in patients with prior hospitalization for exacerbation, greater exacerbation frequency, and higher (≥150 cells/μl, ≥150 to <300 cells/μl, or ≥300 cells/μl) baseline blood eosinophil count.

Development of a Nomogram to Predict the Risk of 30-Day Re-Exacerbation for Patients Hospitalized for Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Acute exacerbation (AE) is the main cause of increased disability and mortality for patients with Chronic Obstructive Pulmonary Disease (COPD). Short-term re-exacerbation after discharge is common for in-hospital patients with AECOPD. Thus, we aimed to design a scoring system to effectively predict the 30-day re-exacerbation using simple and easily accessible variables. We retrospectively enrolled 686 cases hospitalized for AECOPD in two Chinese hospitals from 2005 to 2017. A variety of parameters were collected like demographics, clinical manifestations and treatments in stable and AE period. The optimal subset of covariates in the multivariate logistic analysis was identified by the smallest Akaike Information Criterion (AIC) and was further used to develop a practical and reliable nomogram to predict the 30-day re-exacerbation. The efficacy of the nomogram was internally validated by concordance index (C-index) and a calibration plot. The incidence of 30-day re-exacerbation was 15.8%. Based on the smallest AIC, eight easily-accessible parameters were included in the nomogram, including sex, COPD assessment test (CAT) scores, AE with respiratory failure in the previous year, new purulent sputum, new cardiovascular events, combined antibiotic therapy, theophylline therapy for AE and ICU admission. Our nomogram revealed good discriminative ability with the C-index of 0.702. The calibration curve showed good agreement between nomogram-predicted probability and actual observation. Incorporating eight common variables, a nomogram for 30-day re-exacerbation after discharge with high predictive performance was constructed for patients with AECOPD, which was helpful in predicting individualized risk of re-exacerbation and offering individualized post-discharge support.

Determinants of CAT (COPD Assessment Test) scores in a population of patients with COPD in central and Eastern Europe: The POPE study

BACKGROUND

The COPD Assessment Test (CAT) has been proposed to help guide therapy in chronic obstructive pulmonary disease (COPD). It is important to understand the distribution of scores in different COPD populations and their determinants.

METHODS

The POPE study is an international, observational cross-sectional study of COPD subjects in 11 Central and Eastern European countries aimed at characterizing COPD phenotypes. Here we report the analysis of CAT scores with the objective of identifying their determinants, evaluating symptom load and investigating the distribution of scores among the participating countries. Additionally, we investigated the discrepancies between the CAT and modified Medical Research Council (mMRC) scores when used to classify patients according to the GOLD strategy.

RESULTS

The study included 3452 patients (69.2% men, mean forced expiratory volume in 1 s (FEV1% predicted) 52.5%). The mean CAT score was 17.5 (SD = 7.8), ranging from 15.1 in Hungary to 21.2 in Bulgaria. Multiple linear regression analysis showed six variables significantly associated with CAT scores: depression, number of previous exacerbations, 6-min walking distance, FEV1(%), mMRC and country and explained 47.2% of the variance of CAT. According to either CAT or mMRC, up to 23.9% patients would be classified in different GOLD groups.

CONCLUSIONS

The CAT score may be predicted by factors related to COPD severity, depression and exercise capacity, with significant differences in the distribution of CAT scores in different countries. According to our results CAT >10 is not equivalent to mMRC >2 for assessing symptom burden.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT02119494.

A pilot study of daily telemonitoring to predict acute exacerbation in chronic obstructive pulmonary disease

BACKGROUND

Exacerbations of COPD (ECOPD) are important events in the course of COPD and they accelerate the rate of decline of lung function, and exacerbations requiring hospitalization are associated with significant mortality. Therefore, developing approaches of prevention and early treatment of ECOPDs are of special clinical interests. One of such approaches is telecare, including home telemonitoring.

MATERIAL AND METHODS

Daily telemonitoring of HR, BP, SpO₂ and spirometry was performed. Variables were compared using the bootstrap-boosted inference tests: the paired t-test or Wilcoxon signed rank test, depending on data normality, and categorical variables were compared using exact McNemar's test.

RESULTS

Nineteen patients were included to the study. We observed significant decrease in SpO₂ 7 days preceding ECOPD (P = 0.007; Pbootstrap-boosted = 0.005) and increase in number of events of day-to-day decrease in oxygen saturation >4% in the period of 7 days preceding ECOPD versus reference period (P = 0.02).

CONCLUSIONS

Oxygen saturation telemonitoring would be successfully used in predicting ECOPD. Recording of day-to-day decrease in oxygen saturation >4% as alarming events would be effective approach which would be easily implemented in telemonitoring devices, however this outcome should be further validated in larger size samples.

Long-term effects of oxygen-enriched high-flow nasal cannula treatment in COPD patients with chronic hypoxemic respiratory failure

BACKGROUND

This study investigated the long-term effects of humidified high-flow nasal cannula (HFNC) in COPD patients with chronic hypoxemic respiratory failure treated with long-term oxygen therapy (LTOT).

PATIENTS AND METHODS

A total of 200 patients were randomized into usual care ± HFNC. At inclusion, acute exacerbation of COPD (AECOPD) and hospital admissions 1 year before inclusion, modified Medical Research Council (mMRC) score, St George's Respiratory Questionnaire (SGRQ), forced expiratory volume in 1 second (FEV1), 6-minute walk test (6MWT) and arterial carbon dioxide (PaCO2) were recorded. Patients completed phone interviews at 1, 3 and 9 months assessing mMRC score and AECOPD since the last contact. At on-site visits (6 and 12 months), mMRC, number of AECOPD since last contact and SGRQ were registered and FEV1, FEV1%, PaCO2 and, at 12 months, 6MWT were reassessed. Hospital admissions during the study period were obtained from hospital records. Hours of the use of HFNC were retrieved from the high-flow device.

RESULTS

The average daily use of HFNC was 6 hours/day. The HFNC group had a lower AECOPD rate (3.12 versus 4.95/patient/year, p<0.001). Modeled hospital admission rates were 0.79 versus 1.39/patient/year for 12- versus 1-month use of HFNC, respectively (p<0.001). The HFNC group had improved mMRC scores from 3 months onward (p<0.001) and improved SGRQ at 6 and 12 months (p=0.002, p=0.033) and PaCO2 (p=0.005) and 6MWT (p=0.005) at 12 months. There was no difference in all-cause mortality.

CONCLUSION

HFNC treatment reduced AECOPD, hospital admissions and symptoms in COPD patients with hypoxic failure.

Chronic Obstructive Pulmonary Disease in Sweden: An intersectional multilevel analysis of individual heterogeneity and discriminatory accuracy

Socioeconomic, ethnic and gender disparities in Chronic Obstructive Pulmonary Disease (COPD) risk are well established but no studies have applied multilevel analysis of individual heterogeneity and discriminatory accuracy (MAIHDA) within an intersectional framework to study this outcome. We study individuals at the first level of analysis and combinations of multiple social and demographic categorizations (i.e., intersectional strata) at the second level of analysis. Here we used MAIHDA to assess to what extent individual differences in the propensity of developing COPD are at the intersectional strata level. We also used MAIHDA to determine the degree of similarity in COPD incidence of individuals in the same intersectional stratum. This leads to an improved understanding of risk heterogeneity and of the social dynamics driving socioeconomic and demographic disparities in COPD incidence. Using data from 2,445,501 residents in Sweden aged 45–65, we constructed 96 intersectional strata combining categories of age, gender, income, education, civil- and migration status. The incidences of COPD ranged from 0.02% for young, native males with high income and high education who cohabited to 0.98% for older native females with low income and low education who lived alone. We calculated the intra-class correlation coefficient (ICC) that informs on the discriminatory accuracy of the categorizations. In a model that conflated additive and interaction effects, the ICC was good (20.0%). In contrast, in a model that measured only interaction effects, the ICC was poor (1.1%) suggesting that most of the observed differences in COPD incidence across strata are due to the main effects of the categories used to construct the intersectional matrix while only a minor share of the differences are attributable to intersectional interactions. We found conclusive interaction effects. The intersectional MAIHDA approach offers improved information to guide public health policies in COPD prevention, and such policies should adopt an intersectional perspective.

•

We use multilevel analysis of individual heterogeneity and discriminatory accuracy.

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There is a clear difference in COPD incidence between intersectional strata.

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Intersectionality improves mapping of socioeconomic differences in COPD incidence.

•

Preventive measures should be based on intersectional rather than classic analyses.

Risk Factors for Depression in Patients with Chronic Obstructive Pulmonary Disease

Background

Depression is a major comorbidity in patients with chronic obstructive pulmonary disease (COPD). The aim of this prospective study was to investigate socio-demographic and clinical factors and serum markers of inflammation, including cytokines that, may be a cause or an association with COPD-related depression.

Material/Methods

This study enrolled 53 patients who were hospitalized in the Department of Respiratory Medicine of Hefei First People’s Hospital, China between October 2015 and October 2016. Patients were consecutively recruited who were diagnosed with COPD and without lower respiratory tract disease, psychiatric disorders, or a family history of cognitive disorders. All patients were investigated for symptoms of depression. Lung function testing included forced expiratory volume in 1 second (FEV₁). Serum levels of C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) were measured.

Results

Of the 53 patients with COPD, 40 (75.47%) patients had symptoms of depression. Univariate analysis showed that gender, smoking, a high level of education, duration of a cough, FEV₁, and serum CRP level were associated with depression. A multivariate logistic regression model identified two risk factors for depression in patients with COPD: serum CRP level and FEV₁.

Conclusions

The findings of this study showed that the risk factors for COPD-related depression included male gender, heavy smoking, higher academic qualifications, and duration of cough, but the two strongest risk factors were a high serum CRP level and low FEV₁.

Depressive status explains a significant amount of the variance in COPD assessment test (CAT) scores

Background

COPD assessment test (CAT) is a short, easy-to-complete health status tool that has been incorporated into the multidimensional assessment of COPD in order to guide therapy; therefore, it is important to understand the factors determining CAT scores.

Methods

This is a post hoc analysis of a cross-sectional, observational study conducted in respiratory medicine departments and primary care centers in Spain with the aim of identifying the factors determining CAT scores, focusing particularly on the cognitive status measured by the Mini-Mental State Examination (MMSE) and levels of depression measured by the short Beck Depression Inventory (BDI).

Results

A total of 684 COPD patients were analyzed; 84.1% were men, the mean age of patients was 68.7 years, and the mean forced expiratory volume in 1 second (%) was 55.1%. Mean CAT score was 21.8. CAT scores correlated with the MMSE score (Pearson's coefficient r=-0.371) and the BDI (r=0.620), both p<0.001. In the multivariate analysis, the usual COPD severity variables (age, dyspnea, lung function, and comorbidity) together with MMSE and BDI scores were significantly associated with CAT scores and explained 45% of the variability. However, a model including only MMSE and BDI scores explained up to 40% and BDI alone explained 38% of the CAT variance.

Conclusion

CAT scores are associated with clinical variables of severity of COPD. However, cognitive status and, in particular, the level of depression explain a larger percentage of the variance in the CAT scores than the usual COPD clinical severity variables.