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Henneberger PK, Patel JR, Groene GJ, Beach J, Tarlo SM, Pal TM, Curti S. The effectiveness of removal from exposure and reduction of exposure for managing occupational asthma: Summary of an updated Cochrane systematic review. Am J Ind Med 2021; 64:165-169. [PMID: 33373055 DOI: 10.1002/ajim.23208] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/20/2020] [Accepted: 11/24/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND The objective was to update the 2011 Cochrane systematic review on the effectiveness of workplace interventions for the treatment of occupational asthma. METHODS A systematic review was conducted with the selection of articles and reports through 2019. The quality of extracted data was evaluated, and meta-analyses were conducted using techniques recommended by the Cochrane Handbook for Systematic Reviews of Interventions. RESULTS Data were extracted from 26 nonrandomized controlled before-and-after studies. The mean number of participants per study was 62 and the mean follow-up time was 4.5 years. Compared with continued exposure, removal from exposure had an increased likelihood of improved symptoms and change in spirometry. Reduction of exposure also had more favorable results for symptom improvement than continued exposure, but no difference for change in spirometry. Comparing exposure removal to reduction revealed an advantage for removal with both symptom improvement and change in spirometry for the larger group of patients exposed to low-molecular-weight agents. Also, the risk of unemployment was greater for exposure removal versus reduction. CONCLUSIONS Exposure removal and reduction had better outcomes than continued exposure. Removal from exposure was more likely to improve symptoms and spirometry than reduction among patients exposed to low-molecular-weight agents. The potential benefits associated with exposure removal versus reduction need to be weighed against the potential for unemployment that is more likely with removal from exposure. The findings are based on data graded as very low quality, and additional studies are needed to generate higher quality data.
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Affiliation(s)
- Paul K. Henneberger
- Respiratory Health Division National Institute for Occupational Safety and Health Morgantown West Virginia USA
| | - Jenil R. Patel
- Department of Epidemiology, Human Genetics and Environmental Sciences, School of Public Health The University of Texas Health Science Center at Houston Houston Texas USA
- Department of Epidemiology, Fay W. Boozman College of Public Health University of Arkansas for Medical Sciences Little Rock Arkansas USA
| | - Gerda J. Groene
- Netherlands Center of Occupational Diseases, Academic Medical Center Coronel Institute of Occupational Health Amsterdam The Netherlands
| | - Jeremy Beach
- Department of Medicine University of Alberta Edmonton Alberta Canada
| | - Susan M. Tarlo
- Department of Medicine and Dalla Lana School of Public Health University of Toronto Toronto Ontario Canada
| | - Teake M. Pal
- Netherlands Center of Occupational Diseases, Academic Medical Center Coronel Institute of Occupational Health Amsterdam The Netherlands
| | - Stefania Curti
- Department of Medical and Surgical Sciences University of Bologna Bologna Italy
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Hoy R, Burdon J, Chen L, Miles S, Perret JL, Prasad S, Radhakrishna N, Rimmer J, Sim MR, Yates D, Zosky G. Work-related asthma: A position paper from the Thoracic Society of Australia and New Zealand and the National Asthma Council Australia. Respirology 2020; 25:1183-1192. [PMID: 33020986 PMCID: PMC7702173 DOI: 10.1111/resp.13951] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 08/24/2020] [Accepted: 08/31/2020] [Indexed: 01/10/2023]
Abstract
Work-related asthma (WRA) is one of the most common occupational respiratory conditions, and includes asthma specifically caused by occupational exposures (OA) and asthma that is worsened by conditions at work (WEA). WRA should be considered in all adults with asthma, but especially those with new-onset or difficult to control asthma. Improvement in asthma symptoms when away from work is suggestive of WRA. Clinical history alone is insufficient to diagnose WRA; therefore, objective investigations are required to confirm the presence of asthma and the association of asthma with work activities. Management of WRA requires pharmacotherapy similar to that of non-WRA, however, also needs to take into account control of the causative workplace exposure. Ongoing exposure will likely lead to decline in lung function and worsening asthma control. WRA is a preventable condition but this does rely on increased awareness of WRA and thorough identification and control of all potential occupational respiratory hazards.
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Affiliation(s)
- Ryan Hoy
- Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia.,Allergy, Asthma and Clinical Immunology, The Alfred Hospital, Melbourne, VIC, Australia
| | | | - Ling Chen
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia
| | - Susan Miles
- Department of Medicine, Calvary Mater Newcastle, Newcastle, NSW, Australia
| | - Jennifer L Perret
- Allergy and Lung Health Unit, Centre for Epidemiology and Biostatistics, The University of Melbourne, Melbourne, VIC, Australia
| | - Shivonne Prasad
- Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia
| | - Naghmeh Radhakrishna
- Allergy, Asthma and Clinical Immunology, The Alfred Hospital, Melbourne, VIC, Australia
| | - Janet Rimmer
- Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Malcolm R Sim
- Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia
| | - Deborah Yates
- Department of Thoracic Medicine, St Vincent's Hospital, Sydney, NSW, Australia
| | - Graeme Zosky
- Menzies Institute for Medical Research, Tasmanian School of Medicine, University of Tasmania, Hobart, TAS, Australia
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3
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Henneberger PK, Patel JR, de Groene GJ, Beach J, Tarlo SM, Pal TM, Curti S. Workplace interventions for treatment of occupational asthma. Cochrane Database Syst Rev 2019; 10:CD006308. [PMID: 31593318 PMCID: PMC6781842 DOI: 10.1002/14651858.cd006308.pub4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND The impact of workplace interventions on the outcome of occupational asthma is not well understood. OBJECTIVES To evaluate the effectiveness of workplace interventions on occupational asthma. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE (PubMed); EMBASE(Ovid); NIOSHTIC-2; and CISILO (CCOHS) up to July 31, 2019. SELECTION CRITERIA We included all eligible randomized controlled trials, controlled before and after studies and interrupted time-series of workplace interventions for occupational asthma. DATA COLLECTION AND ANALYSIS Two authors independently assessed study eligibility and risk of bias, and extracted data. MAIN RESULTS We included 26 non-randomized controlled before and after studies with 1,695 participants that reported on three comparisons: complete removal from exposure and reduced exposure compared to continued exposure, and complete removal from exposure compared to reduced exposure. Reduction of exposure was achieved by limiting use of the agent, improving ventilation, or using protective equipment in the same job; by changing to another job with intermittent exposure; or by implementing education programs. For continued exposure, 56 per 1000 workers reported absence of symptoms at follow-up, the decrease in forced expiratory volume in one second as a percentage of a reference value (FEV1 %) was 5.4% during follow-up, and the standardized change in non-specific bronchial hyperreactivity (NSBH) was -0.18.In 18 studies, authors compared removal from exposure to continued exposure. Removal may increase the likelihood of reporting absence of asthma symptoms, with risk ratio (RR) 4.80 (95% confidence interval (CI) 1.67 to 13.86), and it may improve asthma symptoms, with RR 2.47 (95% CI 1.26 to 4.84), compared to continued exposure. Change in FEV1 % may be better with removal from exposure, with a mean difference (MD) of 4.23 % (95% CI 1.14 to 7.31) compared to continued exposure. NSBH may improve with removal from exposure, with standardized mean difference (SMD) 0.43 (95% CI 0.03 to 0.82).In seven studies, authors compared reduction of exposure to continued exposure. Reduction of exposure may increase the likelihood of reporting absence of symptoms, with RR 2.65 (95% CI 1.24 to 5.68). There may be no considerable difference in FEV1 % between reduction and continued exposure, with MD 2.76 % (95% CI -1.53 to 7.04) . No studies reported or enabled calculation of change in NSBH.In ten studies, authors compared removal from exposure to reduction of exposure. Following removal from exposure there may be no increase in the likelihood of reporting absence of symptoms, with RR 6.05 (95% CI 0.86 to 42.34), and improvement in symptoms, with RR 1.11 (95% CI 0.84 to 1.47), as well as no considerable change in FEV1 %, with MD 2.58 % (95% CI -3.02 to 8.17). However, with all three outcomes, there may be improved results for removal from exposure in the subset of patients exposed to low molecular weight agents. No studies reported or enabled calculation of change in NSBH.In two studies, authors reported that the risk of unemployment after removal from exposure may increase compared with reduction of exposure, with RR 14.28 (95% CI 2.06 to 99.16). Four studies reported a decrease in income of 20% to 50% after removal from exposure.The quality of the evidence is very low for all outcomes. AUTHORS' CONCLUSIONS Both removal from exposure and reduction of exposure may improve asthma symptoms compared with continued exposure. Removal from exposure, but not reduction of exposure, may improve lung function compared to continued exposure. When we compared removal from exposure directly to reduction of exposure, the former may improve symptoms and lung function more among patients exposed to low molecular weight agents. Removal from exposure may also increase the risk of unemployment. Care providers should balance the potential clinical benefits of removal from exposure or reduction of exposure with potential detrimental effects of unemployment. Additional high-quality studies are needed to evaluate the effectiveness of workplace interventions for occupational asthma.
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Affiliation(s)
- Paul K Henneberger
- National Institute for Occupational Safety and HealthRespiratory Health Division1095 Willowdale RoadMorgantownWest VirginiaUSA26505
| | - Jenil R Patel
- University of Texas School of Public HealthDepartment of Epidemiology, Human Genetics and Environmental Sciences1200 Pressler ST#W1004aHoustonTexasUSATX 77030
- University of Arkansas for Medical SciencesDepartment of Epidemiology4301 W Markham St, Slot#820Little RockArkansasUSA72205
| | - Gerda J de Groene
- Coronel Institute of Occupational Health, Academic Medical CenterNetherlands Center of Occupational DiseasesPO Box 22660AmsterdamNetherlands1100 DD
| | - Jeremy Beach
- University of AlbertaDepartment of MedicineEdmontonABCanada
| | - Susan M Tarlo
- University of TorontoDepartment of Medicine, and Dalla Lana School of Public HealthToronto Western Hospital EW7‐449399 Bathurst StTorontoONCanadaM5T 2S8
| | - Teake M Pal
- Coronel Institute of Occupational Health, Academic Medical CenterNetherlands Center of Occupational DiseasesPO Box 22660AmsterdamNetherlands1100 DD
| | - Stefania Curti
- University of BolognaDepartment of Medical and Surgical SciencesUO Medicina del Lavoro ‐ Policlinico Sant'Orsola‐MalpighiVia Palagi 9BolognaItaly40138
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Tay TR, Lee JWY, Hew M. Diagnosis of severe asthma. Med J Aust 2019; 209:S3-S10. [PMID: 30453866 DOI: 10.5694/mja18.00125] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Accepted: 05/21/2018] [Indexed: 02/01/2023]
Abstract
Patients with asthma that is uncontrolled despite high intensity medication can present in both primary and specialist care. An increasing number of novel (and expensive) treatments are available for patients who fail conventional asthma therapy, but these may not be appropriate for all such patients. It is essential that a rigorous evaluation process be undertaken for these patients to identify those with biologically severe asthma who will require novel therapies, and those who may improve with control of contributory factors. In this article, we describe three key steps in the diagnostic evaluation process for severe asthma. The first step is confirmation of asthma diagnosis with objective evidence of variable airflow obstruction. The second involves management of contributory factors such as non-adherence, poor inhaler technique, ongoing asthma triggers, and comorbidities. The third step involves phenotyping and endotyping of patients with severe asthma. We provide a practical approach to implementing these measures in both primary and secondary care.
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Affiliation(s)
| | | | - Mark Hew
- The Alfred Hospital, Melbourne, VIC
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5
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Engineered Nanomaterials and Occupational Allergy. CURRENT TOPICS IN ENVIRONMENTAL HEALTH AND PREVENTIVE MEDICINE 2017. [DOI: 10.1007/978-981-10-0351-6_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Radon K, Nowak D, Vogelberg C, Ruëff F. Career Advice for Young Allergy Patients. DEUTSCHES ARZTEBLATT INTERNATIONAL 2016; 113:519-24. [PMID: 27581504 PMCID: PMC5012160 DOI: 10.3238/arztebl.2016.0519] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/14/2016] [Accepted: 04/14/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND One-third of all young persons entering the work force have a history of atopic disease. Occupationally induced allergy and asthma generally arise in the first few months on the job, while pre-existing symptoms tend to worsen. Young persons with a history of an atopic disease should receive evidence-based advice before choosing a career. METHODS We systematically searched PubMed for cohort studies investigating the new onset of asthma, rhinitis, or hand eczema among job trainees from before the start of training and onward into the first few years on the job. The search revealed 514 articles; we read their abstracts and selected 85 full-text articles for further analysis. 24 of these met the inclusion criteria. RESULTS According to present evidence, atopy and a history of allergic disease (allergic rhinitis, atopic dermatitis) are the main risk factors for occupationally induced disease. The predictive value of a personal history of allergic diseases for the later development of an occupationally induced disease varies from 9% to 64% in the studies we analyzed. It follows that only young people with severe asthma or severe atopic eczema should be advised against choosing a job that is associated with a high risk of allergy, e.g., hairdressing or working with laboratory animals. Young people with a history of other atopic diseases should be counseled about their individual risk profile. CONCLUSION In view of the relatively poor predictive value of pre-existing atopic disease, secondary prevention is particularly important. This includes frequent medical follow-up of the course of symptoms over the first few years on the job. If sensitization or allergic symptoms arise, it should be carefully considered whether exposure reduction will enable the apprentice to stay on the job.
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Affiliation(s)
- Katja Radon
- Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, AllergieZENTRUM, Klinikum der Universität München
- Comprehensive Pneumology Center, DZL, Deutsches Zentrum für Lungenforschung, München
| | - Dennis Nowak
- Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, AllergieZENTRUM, Klinikum der Universität München
- Comprehensive Pneumology Center, DZL, Deutsches Zentrum für Lungenforschung, München
| | | | - Franziska Ruëff
- Department of Dermatology and Allergology, AllergieZENTRUM, Klinikum der Universität München
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Abstract
OBJECTIVE The aim of this review was to understand whether FEV1 decline measured during the follow-up of asthmatic subjects (FEV1 variation between two different measurements at a distance of at least 5 years) may have a role in their management. METHODS Articles, commentaries and reviews relating to the topic were searched in PubMed. RESULTS Patients with an accelerated FEV1 decline (>30 ml/year) may be either steroid-resistant/difficult-to-treat asthmatics or not adequately treated because they are either under-perceivers or poorly adherent to their therapy. Sometimes they may be unable to use devices correctly. Untreated rhinitis and incorrect lifestyle (obesity status, a high-fat diet and lack of exercise) must be considered when facing a pulmonary function decline. Identifying asthmatics with an accelerated FEV1 decline, even with well controlled symptoms, may allow us to make possible treatment adjustments or to remove potentially harmful environmental exposure and suggest a correct lifestyle. Depending on FEV1 decline severity, we may detect different asthma phenotypes. One type is characterized by no/low lung function reduction. Among moderate/severe 'declining' subjects, there may be a group that might be responsive to treatment and a second one with a quicker loss in lung function that may be unresponsive to therapy. CONCLUSION FEV1 decline calculation should be assessed early in clinical practice over the course of time in order to make all possible variations in treatment, environmental exposure and lifestyle more efficacious overall for declining subjects responsive to anti-inflammatory therapy. Further studies are necessary to validate this approach to asthma.
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Affiliation(s)
- Bruno Sposato
- Unit of Pneumology, Misericordia Hospital , Grosseto , Italy
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Jamieson DB, Matsui EC, Belli A, McCormack MC, Peng E, Pierre-Louis S, Curtin-Brosnan J, Breysse PN, Diette GB, Hansel NN. Effects of allergic phenotype on respiratory symptoms and exacerbations in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2013; 188:187-92. [PMID: 23668455 DOI: 10.1164/rccm.201211-2103oc] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
RATIONALE Chronic obstructive pulmonary disease (COPD) guidelines make no recommendations for allergy diagnosis or treatment. OBJECTIVES To determine whether an allergic phenotype contributes to respiratory symptoms and exacerbations in patients with COPD. METHODS Two separate cohorts were analyzed: National Health and Nutrition Survey III (NHANES III) and the COPD and domestic endotoxin (CODE) cohort. Subjects from NHANES III with COPD (n = 1,381) defined as age > 40 years, history of smoking, FEV1/FVC < 0.70, and no diagnosis of asthma were identified. The presence of an allergic phenotype (n = 296) was defined as self-reported doctor diagnosed hay fever or allergic upper respiratory symptoms. In CODE, former smokers with COPD (n = 77) were evaluated for allergic sensitization defined as a detectable specific IgE to perennial allergens. Bivariate and multivariate models were used to determine whether an allergic phenotype was associated with respiratory symptoms and exacerbations. MEASUREMENTS AND MAIN RESULTS In NHANES III, multivariate analysis revealed that individuals with allergic phenotype were more likely to wheeze (odds ratio [OR], 2.1; P < 0.01), to have chronic cough (OR, 1.9; P = 0.01) and chronic phlegm (OR, 1.5; P < 0.05), and to have increased risk of COPD exacerbation requiring an acute doctor visit (OR, 1.7; P = 0.04). In the CODE cohort, multivariate analysis revealed that sensitized subjects reported more wheeze (OR, 5.91; P < 0.01), more nighttime awakening due to cough (OR, 4.20; P = 0.03), increased risk of COPD exacerbations requiring treatment with antibiotics (OR, 3.79; P = 0.02), and acute health visits (OR, 11.05; P < 0.01). An increasing number of sensitizations was associated with a higher risk for adverse health outcomes. CONCLUSIONS Among individuals with COPD, evidence of an allergic phenotype is associated with increased respiratory symptoms and risk of COPD exacerbations.
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Affiliation(s)
- Daniel B Jamieson
- Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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Jares EJ, Baena-Cagnani CE, Gómez RM. Diagnosis of occupational asthma: an update. Curr Allergy Asthma Rep 2013; 12:221-31. [PMID: 22467203 DOI: 10.1007/s11882-012-0259-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Work-related asthma (WRA) includes patients with sensitizer- and/or irritant-induced asthma in the workplace, as well as patients with preexisting asthma that is worsened by work factors. WRA is underdiagnosed; thus, the diagnosis is critical to prevent disease progression and its potential for morbidity and mortality. The interview is the first diagnostic tool to be used by physicians, and the question, "Does asthma improve away from work?" is of the highest sensitivity. However, history can show numerous false positives, and the relationships between asthma worsening and work should be confirmed by objective methods such as peak expiratory flow (PEF) at and away from work. PEF sensitivity and specificity can be enhanced in combination with nonspecific bronchial hyperresponsiveness to histamine/methacholine (NSBP) before and after 2 weeks at work and a similar period off work. Immunologic testing, especially skin prick test (SPT) or specific IgE, is useful for high molecular weight allergens and some low molecular weight agents. Other immunologic tests, as well as induced sputum, measurement of exhaled nitric oxide, exhaled breath condensate, and specific inhalation challenge (SIC) are methods that contribute to the diagnosis and are typically performed at specialized facilities. A diagnosis of occupational asthma (OA) should no longer be based on a compatible history only but should be confirmed by means of objective testing. SIC is the diagnostic gold standard. When SIC is not available, the combination of PEF measurement, NSBP test , a specific SPT, or specific IgE may be an appropriate alternative in diagnosing OA.
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Affiliation(s)
- Edgardo J Jares
- Immunology and Allergy Unit, Hospital Nacional Alejandro Posadas, Pcia de Buenos Aires, Argentina.
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Mathew J, Aronow WS, Chandy D. Therapeutic options for severe asthma. Arch Med Sci 2012; 8:589-97. [PMID: 23056066 PMCID: PMC3460493 DOI: 10.5114/aoms.2012.30280] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 03/22/2012] [Accepted: 03/22/2012] [Indexed: 11/17/2022] Open
Abstract
As the overall prevalence of asthma has escalated in the past decades, so has the population of patients with severe asthma. This condition is often difficult to manage due to the relative limitation of effective therapeutic options for the physician and the social and economic burden of the disease on the patient. Management should include an evaluation and elimination of modifiable risk factors such as smoking, allergen exposure, obesity and non-adherence, as well as therapy for co-morbidities like gastro-esophageal reflux disease and obstructive sleep apnea. Current treatment options include conventional agents such as inhalational corticosteroids, long acting β(2) agonists, leukotriene antagonists, and oral corticosteroids. Less conventional treatment options include immunotherapy with methotrexate, cyclosporine and tacrolimus, biological drugs like monoclonal antibodies, tumor necrosis factor-α blockers and oligonucleotides, phosphodiesterase inhibitors, antimicrobials and bronchial thermoplasty.
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Affiliation(s)
- Jilcy Mathew
- Divisions of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, New York Medical College, Valhalla, USA
| | - Wilbert S. Aronow
- Divisions of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, New York Medical College, Valhalla, USA
- Cardiology Division, Department of Medicine, New York Medical College, Valhalla, USA
| | - Dipak Chandy
- Divisions of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, New York Medical College, Valhalla, USA
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Leclere M, Lavoie-Lamoureux A, Joubert P, Relave F, Setlakwe EL, Beauchamp G, Couture C, Martin JG, Lavoie JP. Corticosteroids and antigen avoidance decrease airway smooth muscle mass in an equine asthma model. Am J Respir Cell Mol Biol 2012; 47:589-96. [PMID: 22721832 DOI: 10.1165/rcmb.2011-0363oc] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Recent studies suggest that airway smooth muscle remodeling is an early event in the course of asthma. Little is known of the effects of long-term antigen avoidance and inhaled corticosteroids on chronically established airway remodeling. We sought to measure the effects of inhaled corticosteroids and antigen avoidance on airway remodeling in the peripheral airways of horses with heaves, a naturally occurring asthma-like disease. Heaves-affected adult horses with ongoing airway inflammation and bronchoconstriction were treated with fluticasone propionate (with and without concurrent antigen avoidance) (n = 6) or with antigen avoidance alone (n = 5). Lung function and bronchoalveolar lavage were performed at multiple time points, and peripheral lung biopsies were collected before and after 6 and 12 months of treatment. Lung function improved more quickly with inhaled corticosteroids, but eventually normalized in both groups. Inflammation was better controlled with antigen avoidance. During the study period, corrected smooth muscle mass decreased from 12.1 ± 2.8 × 10(-3) and 11.3 ± 1.2 × 10(-3) to 8.3 ± 1.4 × 10(-3) and 7.9 ± 1.0 × 10(-3) in the antigen avoidance and fluticasone groups, respectively (P = 0.03). At 6 months, smooth muscle mass was significantly smaller compared with baseline only in the fluticasone-treated animals. The subepithelial collagen area was lower at 12 months than at baseline in both groups. During the study period, airway smooth muscle remodeling decreased by approximately 30% in both groups, although the decrease was faster in horses receiving inhaled corticosteroids. Inhaled corticosteroids may accelerate the reversal of smooth muscle remodeling, even if airway inflammation is better controlled with antigen avoidance.
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Affiliation(s)
- Mathilde Leclere
- Department of Veterinary Clinical Sciences, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
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