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Background: The Global Initiative for Obstructive Lung Disease (GOLD) does not promote diffusing capacity for carbon monoxide (Dlco) values in the evaluation of COPD. In GOLD spirometric stage I COPD patients, the clinical and prognostic impact of a low Dlco has not been explored.Research Question: Could a Dlco threshold help define an increased risk of death and a different clinical presentation in these patients?Study Design and Methods: GOLD stage I COPD patients (n = 360) were enrolled and followed over 109 ± 50 months. Age, sex, pack-years' history, BMI, dyspnea, lung function measurements, exercise capacity, BODE index, and history of exacerbations were recorded. A cutoff value for Dlco was identified for all-cause mortality and the clinical and physiological characteristics of patients above and below the threshold compared. Cox regression analysis explored the predictive power of that cutoff value for all-cause mortality.Results: A Dlco cutoff value of <60% predicted was associated with all-cause mortality (Dlco ≥ 60%: 9% vs Dlco < 60%: 23%, P = .01). At a same FEV1% predicted and Charlson score, patients with Dlco < 60% had lower BMI, more dyspnea, lower inspiratory capacity (IC)/total lung capacity (TLC) ratio, lower 6-min walk distance (6MWD), and higher BODE. Cox multiple regression analysis confirmed that after adjusting for age, sex, pack-years history, smoking status, and BMI, a Dlco < 60% is associated with all-cause mortality (hazard ratio [HR], 95% CI = 3.37, 1.35-8.39; P = .009) INTERPRETATION: In GOLD I COPD patients, a Dlco < 60% predicted is associated with increased risk of death and worse clinical presentation. What the cause(s) of this association are and whether they can be treated need to be determined. [ABSTRACT FROM AUTHOR]

Background: The value of the single-breath diffusing capacity of the lungs for carbon monoxide (Dlco) relates to outcomes for patients with COPD. However, little is known about the natural course of Dlco over time, intersubject variability, and factors that may influence Dlco progression.Research Question: What is the natural course of Dlco in patients with COPD over time, and which other factors, including sex differences, could influence this progression?Study Design and Methods: We phenotyped 602 smokers (women, 33%), of whom 506 (84%) had COPD and 96 (16%) had no airflow limitation. Lung function, including Dlco, was monitored annually over 5 years. A random coefficients model was used to evaluate Dlco changes over time.Results: The mean (± SE) yearly decline in Dlco % in patients with COPD was 1.34% ± 0.015%/y. This was steeper compared with non-COPD control subjects (0.04% ± 0.032%/y; P = .004). Sixteen percent of the patients with COPD, vs 4.3% of the control subjects, had a statistically significant Dlco % slope annual decline (4.14%/y). At baseline, women with COPD had lower Dlco values (11.37% ± 2.27%; P < .001) in spite of a higher FEV1 % than men. Compared with men, women with COPD had a steeper Dlco annual decline of 0.89% ± 0.42%/y (P = .039).Interpretation: Patients with COPD have an accelerated decline in Dlco compared with smokers without the disease. However, the decline is slow, and a testing interval of 3 to 4 years may be clinically informative. The lower and more rapid decline in Dlco values in women, compared with men, suggests a differential impact of sex in gas exchange function.Trial Registry: ClinicalTrials.gov; No.: NCT01122758; URL: www.clinicaltrials.gov. [ABSTRACT FROM AUTHOR]

Background: Despite the existing evidence-based smoking cessation interventions, chances of achieving that goal in real life are still low among patients with COPD. We sought to evaluate the clinical consequences of changes in smoking habits in a large cohort of patients with COPD.Methods: CHAIN (COPD History Assessment in Spain) is a Spanish multicenter study carried out at pulmonary clinics including active and former smokers with COPD. Smoking status was certified by clinical history and co-oximetry. Clinical presentation and disease impact were recorded via validated questionnaires, including the London Chest Activity of Daily Living (LCADL) and the Hospital Anxiety and Depression Scale (HADS). No specific smoking cessation intervention was carried out. Factors associated with and clinical consequences of smoking cessation were analyzed by multivariate regression and decision tree analyses.Results: One thousand and eighty-one patients with COPD were included (male, 80.8%; age, 65.2 [SD 8.9] years; FEV1, 60.2 [20.5]%). During the 2-year follow-up time (visit 2, 906 patients; visit 3, 791 patients), the majority of patients maintained the same smoking habit. Decision tree analysis detected chronic expectoration as the most relevant variable to identify persistent quitters in the future, followed by an LCADL questionnaire (cutoff 9 points). Total anxiety HADS score was the most relevant clinical impact associated with giving up tobacco, followed by the LCADL questionnaire with a cutoff value of 10 points.Conclusions: In this real-life prospective COPD cohort with no specific antismoking intervention, the majority of patients did not change their smoking status. Our study also identifies baseline expectoration, anxiety, and dyspnea with daily activities as the major determinants of smoking status in COPD.Trial Registry: ClinicalTrials.gov; No. NCT01122758; URL: www.clinicaltrials.gov. [ABSTRACT FROM AUTHOR]