Differences in the Quantitative HRCT Characteristics of Patients with Asthma, COPD and Asthma-COPD Overlap and Their Relationships with Pulmonary Function.

Purpose: We compared pulmonary function indices and quantitative CT parameters of airway remodeling, air trapping, and emphysema in asthmatic patients and patients with COPD and asthma-COPD overlap (ACO) and explored their relationships with airflow limitation. Patients and Methods: Patients with asthma (n=48), COPD (n=52), and ACO (n=30) and controls (n=54) who completed pulmonary function tests and HRCT scans were retrospectively enrolled in our study. Quantitative CT analysis software was used to assess emphysema (LAA%), airway wall dimensions (wall area (WA), luminal area (LA), and wall area percentage (WA%)), and air trapping ((relative volume change of -860 HU to -950 HU (RVC-860 to-950) and the expiration-to-inspiration ratio of the mean lung density (MLDE/I))). Differences in pulmonary function and HRCT parameters were compared among the groups. Spearman correlation analysis and regression analysis were utilized to explore structure‒function relationships. Results: The LAA% in COPD and ACO patients was significantly greater than that in asthmatic patients and controls. The WA% and WA in COPD and ACO patients were greater than those in controls, whereas the WA% and LA between asthmatic patients and controls reached statistical significance. The RVC-860 to -950 levels decreased in the following order: ACO, COPD, and asthma. RVC-860 to -950 independently predicted FEV1% in asthmatic patients; LAA% and MLDE/I in COPD patients; and LAA%, WA% and RVC-860 to -950 in ACO patients. Conclusion: Comparable emphysema was observed in patients with COPD and ACO but not in asthmatic patients. All patients exhibited proximal airway remodeling. The bronchi were thickened outward in COPD and ACO patients but are thickened inward in asthmatic patients. Furthermore, air trapping in ACO patients was the most severe among all the groups. Indirect lung densitometry measurements might be more predictive of the degree of airflow limitation than direct airway measurements in obstructive airway diseases.

Current situation of asthma-COPD overlap in Chinese patients older than 40 years with airflow limitation: a multicenter, cross-sectional, non-interventional study.

BACKGROUND AND AIMS: Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) is poorly recognized in China. Our study determined the distribution of ACO and its clinical characteristics among patients (aged ⩾40 years) with airflow limitation at Chinese tertiary hospitals. METHODS: This cross-sectional, non-interventional study (NCT02600221), conducted between December 2015 and October 2016 in 20 Tier-3 Chinese hospitals, included patients aged ⩾40 years with post-bronchodilator (BD) FEV1/FVC <0.7. The primary variable was distribution of ACO in adults with post-BD forced expiratory volume /forced vital capacity (FEV1/FVC) <0.7 based on Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2015 and 2017 reports. Other variables included determination of characteristics of ACO and its clinical recognition rate. RESULTS: In 2003 patients (mean age 62.30 ± 9.86 years), distribution of ACO, COPD and asthma were 37.40%, 48.50% and 14.10%, respectively. Proportions of patients with A, B, C and D grouping were 11.70%, 31.00%, 6.90% and 50.30% as per GOLD 2017, whereas they were 15.10%, 51.10%, 3.60% and 30.20% as per GOLD 2015. Similar clinical symptoms were reported in all three groups. A higher percentage of ACO patients presented with dyspnea, wheezing and chest tightness. Compared with the COPD group, a greater proportion of ACO patients reported wheezing (74.6% and 65.40%), while a lower proportion in the ACO group reported cough (79.40% versus 82.70%) and expectoration (76.50% versus 81.60%). Blood eosinophil count ⩾0.3 × 109/L was observed in 34.6% of ACO patients. The clinical recognition rate of ACO was 31.4%. CONCLUSION: Despite ACO affecting two-fifths of the study population, the initial diagnosis rate was low at 6% in China, thus warranting concerted efforts to improve ACO diagnosis. CLINICALTRIALS.GOV: [ClinicalTrials.gov identifier: NCT02600221] registered 22 October 2015, https://clinicaltrials.gov/ct2/show/NCT02600221The reviews of this paper are available via the supplemental material section.

Visual and Quantitative Assessments of Regional Xenon-Ventilation Using Dual-Energy CT in Asthma-Chronic Obstructive Pulmonary Disease Overlap Syndrome: A Comparison with Chronic Obstructive Pulmonary Disease.

OBJECTIVE: To assess the regional ventilation in patients with asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) using xenon-ventilation dual-energy CT (DECT), and to compare it to that in patients with COPD. MATERIALS AND METHODS: Twenty-one patients with ACOS and 46 patients with COPD underwent xenon-ventilation DECT. The ventilation abnormalities were visually determined to be 1) peripheral wedge/diffuse defect, 2) diffuse heterogeneous defect, 3) lobar/segmental/subsegmental defect, and 4) no defect on xenon-ventilation maps. Emphysema index (EI), airway wall thickness (Pi10), and mean ventilation values in the whole lung, peripheral lung, and central lung areas were quantified and compared between the two groups using the Student's t test. RESULTS: Most patients with ACOS showed the peripheral wedge/diffuse defect (n = 14, 66.7%), whereas patients with COPD commonly showed the diffuse heterogeneous defect and lobar/segmental/subsegmental defect (n = 21, 45.7% and n = 20, 43.5%, respectively). The prevalence of ventilation defect patterns showed significant intergroup differences (p < 0.001). The quantified ventilation values in the peripheral lung areas were significantly lower in patients with ACOS than in patients with COPD (p = 0.045). The quantified Pi10 was significantly higher in patients with ACOS than in patients with COPD (p = 0.041); however, EI was not significantly different between the two groups. CONCLUSION: The ventilation abnormalities on the visual and quantitative assessments of xenon-ventilation DECT differed between patients with ACOS and patients with COPD. Xenon-ventilation DECT may demonstrate the different physiologic changes of pulmonary ventilation in patients with ACOS and COPD.

Analysis of Blood Biomarkers in Patients with Chronic Obstructive Pulmonary Disease (COPD) and with Asthma-COPD Overlap (ACO).

Chronic obstructive pulmonary disease (COPD) is a heterogeneous entity with different clinical phenotypes, such as asthma-COPD overlap (ACO). The aim of this retrospective study was to compare routine blood biomarkers in patients with ACO and the remaning COPD phenotypes. Data were collected from stable COPD patients visited in during 2018, including C-reactive protein (CRP), fibrinogen, neutrophyl/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR).A total of 77 patients with COPD were included, 24 (31%) fulfilled the diagnosis of ACO. Clinically, patients with ACO presented more dyspnoea and wheezing. Regarding laboratory parameters, both groups had low levels of lymphocytes, especially the non-ACO group (24.2% vs. 29.3%; p = 0.031), patients with ACO had significantly higher eosinophil counts (4.7% vs. 1.9%; p < 0.001) but a lower percentage of neutrophils (56.8% vs. 64.7%; p = 0.003), NLR and PLR (2.5 vs. 3.8; p = 0.013 and 115 vs. 160; p = 0.063, respectively). In conclusion, besides the expected eosinophilic inflammation in patients with ACO, both groups had low levels of lymphocytes, especially the non-ACO group. The low levels of lymphocytes, in particular in non-ACO patients, should be confirmed in larger studies.

Clinical Phenotypes of Atopy and Asthma in COPD: A Meta-analysis of SPIROMICS and COPDGene.

BACKGROUND: Little is known about the concordance of atopy with asthma COPD overlap. Among individuals with COPD, a better understanding of the phenotypes characterized by asthma overlap and atopy is needed to better target therapies. RESEARCH QUESTION: What is the overlap between atopy and asthma status among individuals with COPD, and how are categories defined by the presence of atopy and asthma status associated with clinical and radiologic phenotypes and outcomes in the Genetic Epidemiology of COPD Study (COPDGene) and Subpopulation and Intermediate Outcome Measures in COPD Study (SPIROMICS)? STUDY DESIGN AND METHODS: Four hundred three individuals with COPD from SPIROMICS and 696 individuals from COPDGene with data about specific IgEs to 10 common allergens and mixes (simultaneous assessment of combination of allergens in similar category) were included. Comparison groups were defined by atopic and asthma status (neither, atopy alone, atopic asthma, nonatopic asthma, with atopy defined as any positive specific IgE (≥0.35 KU/L) to any of the 10 allergens or mixes and asthma defined as self-report of doctor-diagnosed current asthma). Multivariable regression analyses (linear, logistic, and zero inflated negative binomial where appropriate) adjusted for age, sex, race, lung function, smoking status, pack-years smoked, and use of inhaled corticosteroids were used to determine characteristics of groups and relationship with outcomes (exacerbations, clinical outcomes, CT metrics) separately in COPDGene and SPIROMICS, and then adjusted results were combined using meta-analysis. RESULTS: The prevalence of atopy was 35% and 36% in COPD subjects from SPIROMICS and COPDGene, respectively, and less than 50% overlap was seen between atopic status with asthma in both cohorts. In meta-analysis, individuals with nonatopic asthma had the most impaired symptom scores (effect size for St. George's Respiratory Questionnaire total score, 4.2; 95% CI, 0.4-7.9; effect size for COPD Assessment Test score, 2.8; 95% CI, 0.089-5.4), highest risk for exacerbations (incidence rate ratio, 1.41; 95% CI, 1.05-1.88) compared with the group without atopy or asthma. Those with atopy and atopic asthma were not at increased risk for adverse outcomes. INTERPRETATION: Asthma and atopy had incomplete overlap among former and current smokers with COPD in COPDGene and SPIROMICS. Nonatopic asthma was associated with adverse outcomes and exacerbation risk in COPD, whereas groups having atopy alone and atopic asthma had less risk.

Dynamic-Ventilatory Digital Radiography in Air Flow Limitation: A Change in Lung Area Reflects Air Trapping.

OBJECTIVE: The aim of this study was to determine the utility of dynamic-ventilatory digital radiography (DR) for pulmonary function assessment in patients with airflow limitation. METHODS: One hundred and eighteen patients with airflow limitation (72 patients with lung cancer before surgery, 35 patients with chronic obstructive pulmonary disease [COPD], 6 patients with asthma, and 5 patients with asthma-COPD overlap syndrome) were assessed with dynamic-ventilatory DR. The patients were instructed to inhale and exhale slowly and maximally. Sequential chest X-ray images were captured in 15 frames per second using a dynamic flat-panel imaging system. The relationship between the lung area and the rate of change in the lung area due to respiratory motion with respect to pulmonary function was analyzed. RESULTS: The rate of change in the lung area from maximum inspiration to maximum expiration (Rs ratio) was associated with the RV/TLC ratio (r = 0.48, p < 0.01) and the percentage of the predicted FEV1 (r = -0.33, p < 0.01) in patients with airflow limitations. The Rs ratio also decreased in an FEV1-dependent manner. CONCLUSION: The rate of change in the lung area due to respiratory motion evaluated with dynamic DR reflects air trapping. Dynamic DR is a potential tool for the comprehensive assessment of pulmonary function in patients with COPD.

Triple Therapy with Budesonide/Glycopyrrolate/Formoterol Fumarate Improves Inspiratory Capacity in Patients with Asthma-Chronic Obstructive Pulmonary Disease Overlap.

Purpose: Asthma-chronic obstructive pulmonary disease overlap (ACO), characterized by airway limitation, is an important condition with high incidence and mortality. Although some guidelines recommend triple therapy with inhaled corticosteroids/long-acting muscarinic antagonists/long-acting ß2 agonists, this treatment approach is based on the extrapolation of data from studies of asthma or chronic obstructive pulmonary disease (COPD) alone. Methods: A 12-week, randomized, open-label cross-over pilot study was conducted in 19 patients with ACO to investigate the effect of triple therapy with glycopyrrolate (GLY) 50 µg/day on budesonide/formoterol fumarate (BUD/FORM) 640/18 µg/day. The study period included a 4-week wash-out, 4-week run-in, and 4-week treatment period. Respiratory function tests, fractional exhaled nitric oxide (FeNO), a COPD assessment test (CAT) and an asthma control questionnaire (ACQ) were carried out 0, 4, and 8 weeks after randomization. Results: A total of 19 patients with stable ACO (19 males and no females) with a mean age of 70.7 ± 7.6 years (± standard deviation, SD; range 55-83 years) participated in this study. All patients were ex-smokers with a smoking history of 63.1 ± 41.1 pack-years (± SD). Mean values for inspiratory capacity (IC), an index of hyperinflation of the lung that causes exertional dyspnea and reduced exercise, were 1.93 L (± 0.47 L) after the run-in, 1.85 L (± 0.51 L) after the BUD/FORM dual therapy period and 2.11 L (± 0.58 L) after the BUD/GLY/FORM triple therapy period. IC values after the BUD/GLY/FORM triple therapy were significantly higher than those after the run-in (p < 0.02). FeNO values, ACQ, and CAT scores were not significantly different among the run-in, wash-out, and triple-therapy periods. Conclusion: The present pilot study showed that triple therapy with BUD/GLY/FORM results in an improvement in lung function parameters including IC, indicating the potential value of triple therapy as standard treatment for ACO.

Prospective development of practical screening strategies for diagnosis of asthma-COPD overlap.

BACKGROUND AND OBJECTIVE: ACO is a syndrome with high prevalence. However, a pragmatic diagnostic criterion to differentiate ACO is non-existent. We aimed to establish an effective model for screening ACO. METHODS: A multicentre survey was developed to assess the clinical criteria considered important and applicable by pulmonologists for screening ACO. These experts were asked to take the surveys twice. The expert grading method, analytic hierarchy process and ROC curve were used to establish the model, which was then validated by a cross-sectional study of 1066 patients. The GINA/GOLD document was the gold standard in assessing this model. RESULTS: Increased variability of symptoms, paroxysmal wheezing, dyspnoea, historical diagnosis of COPD or asthma, allergic constitution, exposure to risk factors, the FEV1 /FVC < 70% and a positive BDT were important for screening ACO. According to the weight of each criterion, we confirmed that patients meeting six or more of these eight criteria should be considered to have ACO. We called this Chinese screening model for ACO 'CSMA'. It differentiated patients with ACO with a sensitivity of 83.33%, while the sensitivity of clinician-driven diagnosis had a sensitivity of only 42.73%. CONCLUSION: CSMA is a workable model for screening ACO and provides a simple tool for clinicians to efficiently diagnose ACO.

Are the Effects of High-Intensity Exercise Training Different in Patients with COPD Versus COPD+Asthma Overlap?

PURPOSE: This study aimed to investigate whether patients with chronic obstructive pulmonary disease (COPD) presenting asthma overlap (ACO) benefit similarly in comparison to patients with only COPD after a 12-week high-intensity exercise training (ET) program. METHODS: Subjects with a diagnosis of COPD alone or ACO were evaluated and compared before and after a high-intensity ET program composed of walking and cycling plus strengthening exercises of the upper and lower limbs (3 days/week, 3 months, 36 sessions). Assessments included spirometry, bioelectrical impedance, 6-min walk test (6MWT), London Chest Activity of Daily Living Scale (LCADL), Hospital anxiety and depression Scale, modified Medical Research Council Scale (mMRC), Saint George Respiratory Questionnaire (SGRQ), and respiratory and peripheral muscle strength [manovacuometry and 1-repetition maximum test (quadriceps femoris, biceps and triceps brachialis), respectively]. ACO was defined according to Sin et al. (Eur Respir J 48(3):664-673, 2016). RESULTS: The sample was composed of 74 subjects (57% male, age 67 ± 8 years, BMI 26 (21-32) kg/m2, FEV1 47 ± 17%predicted), and 12 (16%) of them were classified as presenting ACO. Both groups improved pulmonary function, 6MWT, peripheral and inspiratory muscle strength, LCADL, and SGRQ after ET (p < 0.005 for all). There were no significant interactions between ACO and COPD on ET effects (p > 0.05 for all). Likewise, there was no difference in the proportion of patients achieving the minimum clinical important difference for 6MWT and mMRC. CONCLUSION: High-intensity exercise training generates similar benefits in patients with COPD regardless of whether presenting asthma overlap or not.

Identification of Asthma-COPD Overlap, Asthma, and Chronic Obstructive Pulmonary Disease Phenotypes in Patients with Airway Obstruction: Influence on Treatment Approach.

BACKGROUND: Many studies have described asthma-COPD overlap (ACO) among patients diagnosed with asthma or chronic obstructive pulmonary disease (COPD), but less so in broad populations of patients with chronic airway obstruction. OBJECTIVE: This study aimed to (i) examine the prevalence of ACO, asthma, and COPD phenotypes among subjects referred for pulmonary function testing (PFT), who had airway obstruction in spirometry (forced expiratory volume in 1 s [FEV1]/forced vital capacity [FVC] <0.7); and (ii) delineate the therapeutic approach of each group. METHODS: Cross-sectional study of patients who were referred for PFT at the Rokach Institute, in Jerusalem. Working definitions were as follows: (a) COPD: post-bronchodilator (BD) FEV1/FVC <0.70; (b) asthma: physician-diagnosed asthma before age 40 and/or minimum post-BD increase in FEV1 or FVC of 12% and 200 mL; and (c) ACO: the combination of the 2. Demographics, smoking habits, episodes of exacerbation, health-related quality of life (HRQL), and respiratory medication utilization were analyzed. RESULTS: Of 3,669 referrals from January 1 to April 30, 2017, 1,220 had airway obstruction of which 215 were included. Of these, 82 (38.1%) had ACO, 49 (22.8%) asthma, and 84 (39.1%) COPD. ACO subjects tended to (a) be predominantly female; (b) be older than asthmatics, (c) be smokers; (d) have worse HRQL in the activity domain; and (d) have more exacerbations. Treatment of ACO and COPD patients differed from that of asthmatics, but not from each other, in the proportion of subjects on maintenance treatment, use of LABA, LAMA, and ICS, alone or in combination, and in the number of inhaler devices used by patients. CONCLUSION: ACO represented >1/3 of patients referred for PFT. Despite a clearly identifiable phenotype, ACO patients received treatment similar to COPD patients, suggesting poor ACO identification. Our data emphasize the need to raise the awareness of ACO among clinicians, in order to guide better recognition and appropriate treatment in individual patients.

Lung air trapping lowers respiratory arousal threshold and contributes to sleep apnea pathogenesis in COPD patients with overlap syndrome.

STUDY OBJECTIVES: Overlap syndrome occurs when obstructive sleep apnea (OSA) and chronic obstructive pulmonary disorder (COPD) coexist in the same patient. Although several studies highlighted the importance of clinical phenotyping in OSA, the trait contribution to OSA pathogenesis in overlap syndrome has not been investigated. With this pilot study, we aimed to measure OSA determinants and their relationship with functional respiratory parameters in a sample of patients with overlap syndrome. In particular, we hypothesize that patients with COPD have in the low arousal threshold a major contributor for the development of OSA. METHODS: Ten consecutive non-hypercapnic COPD patients (body mass index<35 kg/m2) suffering from overlap syndrome with no other relevant comorbidities underwent a phenotyping polysomnography. Traits were measured with CPAP dial-downs. RESULTS: Arousal threshold was found to be inversely associated to functional measures of lung air trapping and static hyperinflation. Particularly, correlations with residual volume (r2 = 0.49, p =  0.024) and residual volume to total lung capacity ratio (r2 = 0.48, p =  0.026) were evident. Only 20% of patients showed a high upper airway passive collapsibility as single pathological trait. In contrast, among those patients with multiple altered traits (6 out of 10), all had an elevated loop gain and 4 (∼65%) a low arousal threshold. CONCLUSIONS: High loop gain and particularly low arousal threshold seem important contributors to OSA pathogenesis and severity in patients with COPD. Recognizing in COPD patients these features as key traits may open avenues for personalized medicine in the field of overlap syndrome.

Clinical Characteristics Of Patients With Asthma COPD Overlap (ACO) In Australian Primary Care.

Purpose: Many older adults with a history of smoking and asthma develop clinical features of both asthma and COPD, an entity sometimes called asthma-COPD overlap (ACO). Patients with ACO may be at higher risk of poor health outcomes than those with asthma or COPD alone. However, understanding of ACO is limited in the primary care setting and more information is needed to better inform patient management. We aimed to compare the characteristics of patients with ACO or COPD in Australian general practices. Patients and methods: Data were from the RADICALS (Review of Airway Dysfunction and Interdisciplinary Community-based care of Adult Long-term Smokers) trial, an intervention study of an interdisciplinary community-based model of care. Baseline demographic and clinical characteristics, pre- and post-bronchodilator spirometry, dyspnoea and St. George's Respiratory Questionnaire scores were compared between 60 ACO patients and 212 with COPD alone. Results: Pre-bronchodilator Forced Expiratory Volume in 1 second (mean±SD 58.4±14.3 vs 67.5±20.1% predicted) and Forced Vital Capacity (mean 82.1±16.9 v 91.9±17.2% predicted) were significantly lower in the ACO group (p<0.001), but no difference was found in post-bronchodilator spirometry. Demographic and clinical characteristics, dyspnoea, quality of life, comorbidities and treatment prescribed did not differ significantly between groups. Conclusion: This is the first study describing the clinical characteristics of ACO patients in Australian general practices. Our finding of lower pre-bronchodilator lung function in the ACO group compared to those with COPD reinforces the importance of spirometry in primary care to inform management. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12614001155684.

A comparison of diagnostic consistency for asthma-chronic obstructive pulmonary disease overlap and clinical characteristics study.

BACKGROUND: The diagnostic criteria for asthma-chronic obstructive pulmonary disease overlap have not been unified. Different studies have used different criteria, and this has led to diagnostic inconsistencies. METHODS: We collected data of patients who were older than 40 years and hospitalised because of chronic bronchial diseases. One hundred and seventy-one patients were included in this study. We compared seven different diagnostic criteria, examined their consistency, and analysed differences among groups classified with each set. RESULTS: The prevalence of ACO ranged between 7.02 and 27.49% depending on the criteria applied. The patients who met the Soler-Cataluna et al. criteria also met the GesEPOC criteria. Rhee has proposed the strictest diagnostic criteria; hence, the number of patients who met these criteria was the smallest, and those patients also met the diagnostic criteria proposed by the other studies. We found that applying the different sets of criteria did not lead to the selection of the same population, while there were no statistical differences in age, disease duration, allergens, and inflammatory markers. CONCLUSIONS: The diagnostic criteria of ACO have not been unified, which hinders the design and progress of clinical studies that would investigate the ACO phenotypes and underlying mechanisms.

Predictive factors for COPD exacerbations and mortality in patients with overlap syndrome.

INTRODUCTION: Patients with chronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea (OSA)-overlap syndrome-have a substantially greater risk of morbidity and mortality, compared to those with either COPD or OSA alone. OBJECTIVES: The aim of this retrospective study was to identify clinical modifiable factors associated with COPD exacerbations and all-cause mortality in patients with overlap syndrome. METHODS: The electronic records of patients with simultaneous COPD and OSA who had a documented acute exacerbation of COPD during a 42-month period were evaluated for reviewed. A control group of overlap syndrome patients without exacerbations was matched 1:1 for age and body mass index. Vital status and cause of death were assessed through the population death registry. RESULTS: Out of 225 eligible cases, 92 patients had at least one episode of COPD exacerbation. There was no significant association between severity of airflow limitation and apnoea hypopnea index (P = .31). After adjusting for confounding variables, patients who had at least one COPD exacerbation were more likely to be active smokers (P = .01), have poorer lung function (P = .001) and less likely to adhere to continuous positive airway pressure (CPAP) use (P = .03). All-cause mortality was also correlated with low forced expiratory volume in 1 second (P = .006), CPAP use (P = .007), and burden of comorbidities (P < .001). CONCLUSION: Lung function and CPAP use were independent predictors of COPD exacerbations and all-cause mortality in a cohort of patients with overlap syndrome. These factors should be taken into account when considering the management and prognosis of these patients.

Physiological and morphological differences of airways between COPD and asthma-COPD overlap.

Overlap of asthma and COPD has attracted attention recently. We aimed to clarify physiological and morphological differences of the airways between COPD and asthma-COPD overlap (ACO). Respiratory resistance and reactance and three-dimensional computed tomography data were evaluated in 167 patients with COPD. Among them, 43 patients who fulfilled the diagnosis of asthma were defined as having ACO. Among 124 patients with COPD without ACO, 86 with a comparable smoking history and airflow limitation as those with ACO were selected using propensity score matching (matched COPD). The intraluminal area (Ai) and wall thickness (WT) of third- to sixth-generation bronchi were measured and adjusted by body surface area (BSA; Ai/BSA and WT/√BSA, respectively). Patients with ACO had higher respiratory resistance and reactance during tidal breathing, but a smaller gap between the inspiratory and expiratory phases, compared with matched patients with COPD. Patients with ACO had a greater WT/√BSA in third- to fourth-generation bronchi, smaller Ai/BSA in fifth- to sixth-generation bronchi, and less emphysematous changes than did matched patients with COPD. Even when patients with ACO and those with COPD have a comparable smoking history and fixed airflow limitation, they have different physiological and morphological features of the airways.

Practical Guide to the Identification and Diagnosis of Asthma-COPD Overlap (ACO).

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of mortality around the world. COPD is characterised by a heterogeneous clinical presentation and prognosis which may vary according to the clinical phenotype. One of the phenotypes of COPD most frequently studied is the asthma-COPD overlap (ACO), however, there are no universally accepted diagnostic criteria for ACO. It is recognised that the term ACO includes patients with clinical features of both asthma and COPD, such as more intense eosinophilic bronchial inflammation, more severe respiratory symptoms and more frequent exacerbations, but in contrast, it is associated with a better prognosis compared to COPD. More importantly, ACO patients show better response to inhaled corticosteroid treatment than other COPD phenotypes. The diagnosis of ACO can be difficult in clinical practice, and the identification of these patients can be a challenge for non-specialized physicians. We describe how to recognise and diagnose ACO based on a recently proposed Spanish algorithm and by the analysis of three clinical cases of patients with COPD. The diagnosis of ACO is based on the diagnosis of COPD (chronic airflow obstruction in an adult with significant smoking exposure), in addition to a current diagnosis of asthma and/or signficant eosinophilia.

Polysomnographic features of low arousal threshold in overlap syndrome involving obstructive sleep apnea and chronic obstructive pulmonary disease.

PURPOSE: In patients with overlap syndrome (OVS), the pathophysiologies of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease can interact with one another. Focusing on low arousal threshold, the authors evaluated polysomnographic features of OVS patients. METHODS: This retrospective, multicenter study was conducted at three hospitals in Japan. Patients aged ≥ 60 years who underwent polysomnography and pulmonary function testing were reviewed. Severity of airflow limitation (AFL) was classified according to the Global Initiative for Chronic Obstructive Lung Disease criteria. Low arousal threshold was predicted based on the following polysomnography features: lower apnea-hypopnea index (AHI); higher nadir oxygen saturation, and larger hypopnea fraction of total respiratory events. These features were compared among patients with only OSA (n = 126), OVS with mild AFL (n = 16), and OVS with moderate/severe AFL (n = 22). RESULTS: A low arousal threshold was more frequently exhibited by OVS patients with moderate/severe AFL than by those with OSA only (p = 0.016) and OVS with mild AFL (p = 0.026). As forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) decreased in OVS patients, the mean length of apnea decreased (r = 0.388, p = 0.016), hypopnea fractions increased (r = - 0.337, p = 0.039), and AHI decreased (r = 0.424, p = 0.008). FEV1/FVC contributed to low arousal threshold independent of age, sex, smoking history, hospital, or body mass index in all subjects (OR 0.946 [95% CI 0.909-0.984]) and in OVS patients (OR 0.799 [95% CI 0.679-0.940]). CONCLUSIONS: This study first described peculiar polysomnographic features in OVS patients with moderate/severe AFL, suggesting a high prevalence of low arousal threshold.

[Asthma-chronic obstructive pulmonary disease overlap syndrome: clinical-functional profile]. / Síndrome de sobreposición asma-enfermedad pulmonar obstructiva crónica: perfil clínico-funcional.

BACKGROUND: Asthma and Chronic Obstructive Pulmonary Disease (COPD) affects 1 in 10 individuals worldwide. Asthma and COPD overlap syndrome (ACOS) have more symptoms, exacerbations and worse pulmonary function. OBJECTIVE: To evaluate the clinical-functional profile with ACOS who are detected in a second level clinic. METHODS: Retrospective study; 466 patients 18 years and older with COPD and asthma with acceptable spirometries were analyzed. ACOS definition proposed by Montes de Oca and colleagues was used. Patients were divided in three groups: Asthma, COPD and ACOS. Differences were estimated with Chi square and ANOVA with Bonferroni´s adjustment. RESULTS: 79.1% were diagnosed with asthma, 8.1% COPD and 12.6% ACOS. ACOS patients were more symptomatic; the exacerbation frequency during the last year was greater (Asthma: 24.9% vs. COPD: 15.8% vs. ACOS: 39%; p=0.036); in patients with ACOS the magnitude of change in pulmonary function was greater than those with asthma (p=0.000). The severity of obstruction was worse among those patients with COPD and ACOS. Having medical diagnosis of ACOS, dyspnea mMRC >2 and ACT <15 increased the probability of exacerbation during last the year. CONCLUSION: The prevalence of ACOS was 12.6% in our group. The patients with ACOS had the worst disease control, more frequency of previous exacerbations and more severity in lung function.

INTRODUCCIÓN: el asma y la enfermedad pulmonar obstructiva crónica (EPOC) afectan a uno de cada 10 individuos a nivel mundial. Su coexistencia (ACOS) se traduce en mayor frecuencia de síntomas, agudizaciones y en peor función pulmonar. OBJETIVO: evaluar el perfil clínico-funcional de los pacientes con sobreposición asma-EPOC. MÉTODOS: estudio transversal y retrospectivo; se analizaron a 466 pacientes mayores de 18 años con asma y EPOC con espirometrías aceptables. Se usó la definición de ACOS propuesta por Montes de Oca et al. Los pacientes se dividieron en tres grupos: asma, EPOC y ACOS. Se estimaron las diferencias con Chi cuadrada y ANOVA con ajuste de Bonferroni. RESULTADOS: el 79.3% de los pacientes tuvo diagnóstico de asma, el 8.1% de EPOC y el 12.6% de ACOS. Los pacientes con ACOS fueron más sintomáticos; la frecuencia de una exacerbación en el año previo fue significativamente mayor en ellos (asma: 24.9% vs. EPOC: 15.8% vs. ACOS: 39%; p = 0.036); En los pacientes con ACOS, la magnitud del cambio en función pulmonar fue mayor al compararse con los pacientes con asma (p = 0.000). La gravedad de la obstrucción fue mayor entre los grupos de EPOC y ACOS (p = 0.000). Tener el diagnóstico de ACOS, disnea mMRC > 2 y ACT < 15 otorgaron una probabilidad mayor de exacerbaciones el año previo. CONCLUSIÓN: la prevalencia de ACOS fue de 12.6%. Los pacientes con ACOS tenían peor control de la enfermedad, más frecuencia de exacerbaciones previas y mayor gravedad de la función pulmonar.

The many faces of asthma-chronic obstructive pulmonary disease overlap.

PURPOSE OF REVIEW: Asthma and chronic obstructive pulmonary disease (COPD) are common diseases that often overlap. The term asthma-COPD overlap (ACO) has been used to define this entity but there remain several speculations on its exact definition, impact, pathophysiology, clinical features, and management. We reviewed recent publications on ACO to obtain more insight of current knowledge and outline future needs. RECENT FINDINGS: Criteria for ACO vary from one publication to another and the many variable features of these patients underline the need to reconsider the evaluation and approach of patients with overlapping features based on clinical traits and underlying biological mechanisms. Epidemiological studies reveal that ACO patients have generally an increased burden of illness and healthcare use in addition to poorer quality of life (QoL) compared with asthma and higher or equal to COPD. However, their long-term outcome seems better than patients with COPD alone. Various methods have been proposed to evaluate these patients but their usefulness compared to 'classical' investigation of obstructive lung diseases remains speculative and needs further evaluation. Furthermore, there are no formal studies that examined and compared the different treatment strategies of well-characterized patients with ACO as such patients are usually excluded from clinical trials. SUMMARY: ACO is a common condition with variable features and a high burden of disease. There is no consensus on its definition, diagnostic, and clinical features and more research should be done on its optimal management and long-term outcomes.