Burden and Characteristics of Severe Chronic Hypoxemia in a Real-World Cohort of Subjects with COPD.

BACKGROUND: Chronic respiratory failure may occur as a consequence of chronic obstructive pulmonary disease (COPD) and is associated with significant morbidity and mortality. Hypoxemia is determined by underlying disease characteristics and comorbidities. Severe hypoxemia is typically only found in subjects with severe airflow obstruction (FEV1<50% predicted). However, how hypoxemia relates to disease characteristics is not fully understood. METHODS: In the French Initiatives BPCO real-life cohort, arterial blood gases were routinely collected in most patients. Relationships between severe hypoxemia, defined by a Pa02<60 mmHg (8 kPa) and clinical/lung function features, comorbidities and mortality were assessed. In subjects with severe hypoxemia, clinical characteristics and comorbidities were compared between those with non-severe versus severe airflow limitation. Classification and regression trees (CART) were used to define clinically relevant subgroups (phenotypes). RESULTS: Arterial blood gases were available from 887 subjects, of which 146 (16%) exhibited severe hypoxemia. Compared to subjects with a PaO2≥60 mmHg, the severe hypoxemia group exhibited higher mMRC dyspnea score, lower FEV1, higher RV and RV/TLC, more impaired quality of life, lower 6-minute walking distance, less frequent history of asthma, more frequent diabetes and higher 3-year mortality rate (14% versus 8%, p=0.026). Compared to subjects with Pa02<60 mmHg and FEV1<50% (n=115, 13%), those with severe hypoxemia but FEV1≥50% predicted (n=31) were older, had higher BMI, less hyperinflation, better quality of life and a higher rate of diabetes (29% versus 13%, p=0.02). Severe hypoxemia was better related to CART-defined phenotypes than to GOLD ABCD classification. CONCLUSION: In this cohort of stable COPD subjects, severe hypoxemia was associated with worse prognosis and more severe symptoms, airflow limitation and hyperinflation. Compared to subjects with severe hypoxemia and severe airflow limitation, subjects with severe hypoxemia despite non-severe airflow limitation were older, had higher BMI and more diagnosed diabetes. TRIAL REGISTRATION: 04-479.

Relationship between gender and survival in a real-life cohort of patients with COPD.

BACKGROUND: Although COPD affects both men and women, its prevalence is increasing more rapidly in women. Disease outcomes appear different among women with more frequent dyspnea and anxiety or depression but whether this translates into a different prognosis remains to be determined. Our aim was to assess whether the greater clinical impact of COPD in women was associated with differences in 3-year mortality rates. METHODS: In the French Initiatives BPCO real-world cohort, 177 women were matched up to 458 menon age (within 5-year intervals) and FEV1 (within 5% predicted intervals). 3-year mortality rate and survival were analyzed. Univariate and multivariate logistic regression analyses were performed. RESULTS: For a given age and level of airflow obstruction, women with COPD had more severe dyspnea, lower BMI, and were more likely to exhibit anxiety. Nevertheless, three-year mortality rate was comparable among men and women, respectively 11.2 and 10.8%. In a multivariate model, the only factors significantly associated with mortality were dyspnea and malnutrition but not gender. CONCLUSION: Although women with COPD experience higher levels of dyspnea and anxiety than men at comparable levels of age and FEV1, these differences do not translate into variations in 3-year mortality rates. TRIAL REGISTRATION: 04-479.

Predictors in routine practice of 6-min walking distance and oxygen desaturation in patients with COPD: impact of comorbidities.

Background: The 6-min walk test (6MWT) allows exercise tolerance to be assessed, and it has a significant prognostic value in COPD. The goal of this study was to analyse the determinants (obtained in routine practice) of a low 6-min walking distance (6MWD) and exercise-induced desaturation (EID) in COPD, including comorbidities. Methods: Patients were recruited from the real-life French COPD cohort "Initiatives BPCO". A low 6MWD was defined as <350 m. EID was defined by a minimum pulse oxygen saturation (SpO2)<90% and delta SpO2≥4% from baseline. Multivariate logistic regression analyses assessed the influence on 6MWD and EID of age, sex, obesity (body mass index, BMI >30 kg/m2), low BMI (BMI <18.5 kg/m2), modified Medical Research Council (mMRC) dyspnea scale, FEV1% pred, FVC % pred, hyperinflation and comorbidities including cardiovascular diseases. Results: Among 440 patients with available 6MWT data, a 6MWD <350 m was found in 146 patients (33%), which was positively associated in multivariate analyses with age and mMRC and negatively with resting SpO2 and FVC % pred (rescaled r2=0.34), whereas no comorbidity was associated with a low 6WMD. EID was found in 155 patients (35%). This was positively associated with hypertension and negatively with age, obesity, FEV1% pred and resting SpO2 (rescaled r2=0.37). Conclusion: 6MWD and EID exhibit different determinants in COPD with a minor impact of comorbidities limited to hypertension in EID and to obesity, which was unexpectedly associated with less EID. Other variables including age, routine resting lung function and SpO2 were weakly associated with 6MWD and EID. Altogether, these results suggest that 6MWT performance remains difficult to predict with routine clinical/functional parameters.

Relationship between blood eosinophils, clinical characteristics, and mortality in patients with COPD.

In patients with COPD, there is controversy regarding the association of blood eosinophil (Eos) levels with 1) exacerbation frequency and 2) the effect of inhaled corticosteroids for prevention of exacerbations. To determine whether Eos define subgroups of patients exhibiting attributes of COPD clinical phenotypes, we compared clinical features and mortality rates in COPD patients from the Initiatives BPCO French cohort categorized using different thresholds of blood Eos levels. The following data were collected at inclusion: medical and smoking history, occupational exposures, dyspnea, cough and sputum production, exacerbations in the previous year, history of allergy and asthma, nasal symptoms, body mass index, St George Respiratory Questionnaire (SGRQ) total score, post-bronchodilator spirometry, comorbidities, and medications. Three-year survival between groups was compared using Kaplan-Meier analysis. Three sets of analyses were performed to compare patients with ≥2% versus <2%, ≥3% versus <3%, and ≥4% versus <4% Eos. Eos was available in 458 patients (mean age: 62 years, 72% male, mean forced expiratory volume in 1 second: 51% pred), including 235 patients with Eos ≥2% (49%), 149 with Eos ≥3% (33%), and 90 with Eos ≥4% (20%). For all cutoffs, there was no difference between Eos+ and Eos- groups in univariate analyses except for diabetes and SGRQ score (more frequent and more impaired, respectively, in lower Eos categories). In particular, there was no difference in exacerbation rate, history of asthma, or three-year survival. In conclusion, regardless of the cutoff, Eos+ COPD patients exhibited no specific characteristic in terms of symptoms, lung function, exacerbation rate, and prognosis. These findings suggest that the association of higher Eos with exacerbations reported in previous studies could be population specific, which does not support generalizing the use of Eos as a biomarker for COPD phenotyping.

Impact of current cough on health-related quality of life in patients with COPD.

BACKGROUND: Cough and sputum production are frequent in chronic obstructive pulmonary disease (COPD). The objective of this study was to examine the relationship between cough and sputum production and health-related quality of life in COPD. METHODS: A cross-sectional study was conducted in the French Initiatives COPD cohort and assessed cough and sputum production within the past 7 days using the cough and sputum assessment questionnaire (CASA-Q), health-related quality of life, spirometry, smoking status, dyspnea, exacerbations, anxiety and depression, and comorbidities. RESULTS: One hundred and seventy-eight stable COPD patients were included (age, 62 [56-69] years, 128 male, forced expiratory volume in 1 second [FEV1]: 57 [37-72] % predicted) (median [Q1-Q3]). In univariate analyses, health-related quality of life (Saint George's respiratory questionnaire total score) was associated with each CASA-Q domain and with chronic bronchitis, exacerbations, dyspnea, FEV1, depression, and anxiety. All four domains introduced separately were independently associated with health-related quality of life. When introduced together in multivariate analyses, only the cough impact domain remained independently associated with health-related quality of life (R2=0.60). With chronic bronchitis (standard definition) instead of the CASA-Q, the R2 was lower (R2=0.54). CONCLUSION: This study provides evidence that current cough in the previous 7 days is an important determinant of health-related quality of life impairment in stable COPD patients.

Impact of gender on COPD expression in a real-life cohort.

Reports regarding gender-related differences in COPD expression have provided conflicting results. In the French Initiatives BPCO real-world cohort, which contained 688 patients (146 women) when data were extracted, women were matched with men (1:3 ratio: n = 107:275) on age (5-year intervals) and FEV1 (5% predicted intervals) and comparisons were performed using univariate logistic regressions. For a given age and level of airflow obstruction, women with COPD had higher BOD scores due to more pronounced dyspnea and lower BMI, suggesting worse prognosis, and were more likely to exhibit anxiety, suggesting the need for specific assessment and care.

Association of chronic nasal symptoms with dyspnoea and quality-of-life impairment in chronic obstructive pulmonary disease.

BACKGROUND AND OBJECTIVE: Previous studies suggested that chronic nasal symptoms (CNS) are frequent in chronic obstructive pulmonary disease (COPD) subjects, but their contribution to dyspnoea and quality-of-life (QoL) impairment is not clearly established. METHODS: Data from the French COPD cohort 'Initiatives bronchopneumopathie chronique obstructive' were analyzed to assess the frequency of CNS (rhinorrhea, obstruction, anosmia) in COPD patients and analyze their impact and associated risk factors. Univariate and multivariate analyses were performed to assess the relationship between CNS with sociodemographic and anthropometric characteristics, risk factors, respiratory symptoms, spirometry, QoL (Saint George's respiratory questionnaire (SGRQ)), dyspnoea (modified Medical Research Council (mMRC) scale), mood disorders (Hospital Anxiety and Depression Scale (HADS)), number of exacerbations and comorbid conditions. RESULTS: CNS were reported by 115 of 274 COPD subjects (42%). Among them, rhinorrhea and nasal obstruction were reported by 62% and 43%, respectively. In multivariate analysis, COPD patients with CNS had higher SGRQ total scores, corresponding to worse QoL (P = 0.01), while no independent association was found with exacerbations, lung function and HADS. Among SGRQ domains, an independent association was found with the activity score (P = 0.007). When SGRQ score was forced out of the model to avoid redundancy, mMRC score was independently associated with CNS (P = 0.01). Among risk factors, cumulative smoking, hay fever and atopic dermatitis but not occupational exposures were independently associated with CNS. CONCLUSIONS: In this group of COPD subjects, CNS were frequently observed and associated with dyspnoea and poorer QoL. CNS should be systematically assessed and could be a potential target in the management of COPD.

Cough and sputum production are associated with frequent exacerbations and hospitalizations in COPD subjects.

BACKGROUND: Epidemiologic studies indicate that chronic cough and sputum production are associated with increased mortality and disease progression in COPD subjects. Our objective was to identify features associated with chronic cough and sputum production in COPD subjects. METHODS: Cross-sectional analysis of data were obtained in a multicenter (17 university hospitals in France) cohort of COPD patients. The cohort comprised 433 COPD subjects (65 +/- 11 years; FEV(1), 50 +/- 20% predicted). Subjects with (n = 321) and without (n = 112) chronic cough and sputum production were compared. RESULTS: No significant difference was observed between groups for age, FEV(1), body mass index, and comorbidities. Subjects with chronic cough and sputum production had increased total mean numbers of exacerbations per patient per year (2.20 +/- 2.20 vs 0.97 +/- 1.19, respectively; p < 0.0001), moderate exacerbations (1.80 +/- 2.07 vs 0.66 +/- 0.85, respectively; p < 0.0001), and severe exacerbations requiring hospitalizations (0.43 +/- 0.95 vs 0.22 +/- 0.56, respectively; p < 0.02). The total number of exacerbations per patient per year was the only variable independently associated with chronic cough and sputum production. Frequent exacerbations (two or more per patient per year) occurred in 55% vs 22% of subjects, respectively, with and without chronic cough and sputum production (p < 0.0001). Chronic cough and sputum production and decreased FEV(1) were independently associated with an increased risk of frequent exacerbations and frequent hospitalizations. CONCLUSIONS: Chronic cough and sputum production are associated with frequent COPD exacerbations, including severe exacerbations requiring hospitalizations.