Intra-breath changes in respiratory mechanics assessed from multi-frequency oscillometry measurements

Objective. Recent studies in respiratory system impedance (Zrs) with single-frequency oscillometry have demonstrated the utility of novel intra-breath measures of Zrs in the detection of pathological alterations in respiratory mechanics. In the present work, we addressed the feasibility of extracting intra-breath information from Zrs data sets obtained with conventional oscillometry. Approach. Multi-frequency recordings obtained in a pulmonology practice were re-analysed to track the 11 Hz component of Zrs during normal breathing and compare the intra-breath measures to that obtained with a single 10 Hz signal in the same subjects. A nonlinear model was employed to simulate changes in Zrs in the breathing cycle. The values of resistance (R) and reactance (X) at end expiration and end inspiration and their corresponding differences (Delta R and Delta X) were compared. Main results. All intra-breath measures exhibited similar mean values at 10 and 11 Hz in each subject; however, the variabilities were higher at 11 Hz, especially for Delta R and Delta X. The poorer quality of the 11 Hz data was primarily caused by the overlapping of modulation side lobes of adjacent oscillation frequencies. This cross-talk was enhanced by double breathing frequency components due to flow nonlinearities. Significance. Retrospective intra-breath assessment of large or special data bases of conventional oscillometry can be performed to better characterise respiratory mechanics in different populations and disease groups. The results also have implications in the optimum design of multiple-frequency oscillometry (avoidance of densely spaced frequencies) and the use of filtering procedures that preserve the intra-breath modulation information

Oscillometry and pulmonary magnetic resonance imaging in asthma and COPD

Developed over six decades ago, pulmonary oscillometry has re-emerged as a noninvasive and effort-independent method for evaluating respiratory-system impedance in patients with obstructive lung disease. Here, we evaluated the relationships between hyperpolarize

“Trying, But Failing” : The Role of Inhaler Technique and Mode of Delivery in Respiratory Medication Adherence

Recognition of Commercial Support: The Expert Adherence Panel Meeting from which the concepts presented in this article were first discussed and the manuscript submission costs were supported by the Respiratory Effectiveness Group.Peer reviewedPublisher PD

Withdrawal of inhaled corticosteroids versus continuation of triple therapy in patients with COPD in real life: observational comparative effectiveness study

MPOC; Eficàcia; Corticoides inhalatsEPOC; Eficacia; Corticosteroides inhaladosCOPD; Effectiveness; Inhaled corticosteroidsBackground Inhaled corticosteroids (ICS) are indicated for prevention of exacerbations in patients with COPD, but they are frequently overprescribed. ICS withdrawal has been recommended by international guidelines in order to prevent side effects in patients in whom ICS are not indicated. Method Observational comparative effectiveness study aimed to evaluate the effect of ICS withdrawal versus continuation of triple therapy (TT) in COPD patients in primary care. Data were obtained from the Optimum Patient Care Research Database (OPCRD) in the UK. Results A total of 1046 patients who withdrew ICS were matched 1:4 by time on TT to 4184 patients who continued with TT. Up to 76.1% of the total population had 0 or 1 exacerbation the previous year. After controlling for confounders, patients who discontinued ICS did not have an increased risk of moderate or severe exacerbations (adjusted HR: 1.04, 95% confidence interval (CI) 0.94–1.15; p = 0.441). However, rates of exacerbations managed in primary care (incidence rate ratio (IRR) 1.33, 95% CI 1.10–1.60; p = 0.003) or in hospital (IRR 1.72, 95% CI 1.03–2.86; p = 0.036) were higher in the cessation group. Unsuccessful ICS withdrawal was significantly and independently associated with more frequent courses of oral corticosteroids the previous year and with a blood eosinophil count ≥ 300 cells/μL. Conclusions In this primary care population of patients with COPD, composed mostly of infrequent exacerbators, discontinuation of ICS from TT was not associated with an increased risk of exacerbation; however, the subgroup of patients with more frequent courses of oral corticosteroids and high blood eosinophil counts should not be withdrawn from ICS.The study was funded by a Grant from Boehringer Ingelheim

Withdrawal of inhaled corticosteroids versus continuation of triple therapy in patients with COPD in real life : Observational comparative effectiveness study

FUNDING The study was funded by a grant from Boehringer Ingelheim. ACKNOWLEDGMENTS The study was designed and conducted by the Respiratory Effectiveness Group (REG; www.regresearchnetwork.org; Ely, UK) and data was delivered by Optimum Patient Care (OPC; www.optimumpatientcare.org) with support from Derek Skinner.Peer reviewedPublisher PD

Prevalence and Characteristics of Asthma-COPD Overlap in Routine Primary Care Practices

Rationale: Adults may exhibit characteristics of both asthma and chronic obstructive pulmonary disease (COPD), a situation recently described as asthma-COPD overlap (ACO). There is a paucity of information about ACO in primary care. Objectives: To estimate the prevalence and describe characteristics of individuals withACOin primary care practices among patients currently diagnosed with asthma, COPD, or both; and to compare the prevalence and characteristics of ACO among the three source populations. Methods: The Respiratory Effectiveness Group conducted a crosssectional study of individuals ≥40 years old and with ≥2 outpatient primary care visits over a 2-year period in theUKOptimum Patient Care Research Database. Patients were classified into one of three source populations based on diagnostic codes: 1) COPD only, 2) both asthma and COPD, or 3) asthma only.ACOwas defined as the presence of all of the following 1) age ≥40 years, 2) current or former smoking, 3) postbronchodilator airflow limitation (forced expiratory volume in 1 second/ forced vital capacity <0.7), and 4) ≥12% and ≥200 ml reversibility in post-bronchodilator forced expiratory volume in 1 second. Results: Among 2,165 individuals (1,015 COPD only, 395 with both asthma and COPD, and 755 asthma only), the overall prevalence of ACO was 20% (95% confidence interval, 18-23%). Patients with ACO had a mean age of 70 years (standard deviation, 11 yr), 60% were men, 73% were former smokers (the rest were current smokers), and 66% were overweight or obese. Comorbid conditions were common in patients with ACO, including diabetes (53%), cardiovascular disease (36%), hypertension (30%), eczema (23%), and rhinitis (21%). The prevalence of ACO was higher in patients with a diagnosis of both asthma and COPD (32%) compared with a diagnosis of COPD only (20%; P<0.001) or asthma only (14%; P<0.001). Demographic and clinical characteristics of ACO varied across these three source populations. Conclusions: One in five individuals with a diagnosis of COPD, asthma, or both asthma and COPD in primary care settings have ACO based on the Respiratory Effectiveness Group ACO Working group criteria. The prevalence and characteristics of patients with ACO varies across the three source populations

Withdrawal of inhaled corticosteroids versus continuation of triple therapy in patients with COPD in real life: observational comparative effectiveness study

MPOC; Eficàcia; Corticoides inhalatsEPOC; Eficacia; Corticosteroides inhaladosCOPD; Effectiveness; Inhaled corticosteroidsBackground Inhaled corticosteroids (ICS) are indicated for prevention of exacerbations in patients with COPD, but they are frequently overprescribed. ICS withdrawal has been recommended by international guidelines in order to prevent side effects in patients in whom ICS are not indicated. Method Observational comparative effectiveness study aimed to evaluate the effect of ICS withdrawal versus continuation of triple therapy (TT) in COPD patients in primary care. Data were obtained from the Optimum Patient Care Research Database (OPCRD) in the UK. Results A total of 1046 patients who withdrew ICS were matched 1:4 by time on TT to 4184 patients who continued with TT. Up to 76.1% of the total population had 0 or 1 exacerbation the previous year. After controlling for confounders, patients who discontinued ICS did not have an increased risk of moderate or severe exacerbations (adjusted HR: 1.04, 95% confidence interval (CI) 0.94–1.15; p = 0.441). However, rates of exacerbations managed in primary care (incidence rate ratio (IRR) 1.33, 95% CI 1.10–1.60; p = 0.003) or in hospital (IRR 1.72, 95% CI 1.03–2.86; p = 0.036) were higher in the cessation group. Unsuccessful ICS withdrawal was significantly and independently associated with more frequent courses of oral corticosteroids the previous year and with a blood eosinophil count ≥ 300 cells/μL. Conclusions In this primary care population of patients with COPD, composed mostly of infrequent exacerbators, discontinuation of ICS from TT was not associated with an increased risk of exacerbation; however, the subgroup of patients with more frequent courses of oral corticosteroids and high blood eosinophil counts should not be withdrawn from ICS.The study was funded by a Grant from Boehringer Ingelheim

Intraindividual variability in serum alpha-1 antitrypsin levels

Background: Measuring alpha-1 antitrypsin (AAT) serum levels is often the first step when investigating for alpha-1 antitrypsin deficiency (AATD). The purpose of this study was to determine the test-retest reproducibility of AAT serum levels and to determine if between-measurements variability was associated with acute phase markers of inflammation. Methods: We retrospectively analyzed a sample of 255 patients from a community respirology practice with chronic obstructive pulmonary disease (COPD) in whom AAT serum levels were measured twice, on separate visits. White blood cell count and fibrinogen were also measured at the time of the second blood sampling as markers of acute phase inflammation. Intraclass correlation coefficient (ICC), Pearson correlation coefficient, and Bland-Altman analysis were used to document test-retest reproducibility. Regression analyses were used to identify potential correlates of test-retest AAT level differences. Results: Although the 2 AAT serum levels were significantly correlated, the between-measurement agreement was weak (ICC of 0.38 [95% confidence interval (CI), 0.27 to 0.48]; Pearson correlation coefficient of 0.34 [95% CI, 0.23 to 0.44]) and Bland-Altman analysis revealed wide 95% limits of agreement. Considering that an AAT serum level below 1.13g/L should trigger further investigations to confirm the AAT status, discrepancies between the test-retest AAT levels resulted in reconsidering requirement for further investigation in 22% of patients. A significant correlation between the fibrinogen value and the second AAT level was found (r=0.21, p=0.004 [n=173]). Conclusions: Serum AAT levels showed weak intra-individual reproducibility which could lead to AATD status misclassification and potentially a missed diagnosis of AATD.</p