Monaldi archives for chest disease = Archivio Monaldi per le malattie del torace / Fondazione clinica del lavoro, IRCCS [and] Istituto di clinica tisiologica e malattie apparato respiratorio, Università di Napoli, Secondo ateneo
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Monaldi Arch Chest Dis · Jun 2005
Multicenter StudyAsthma is not a common cause of severe chronic respiratory failure in non-smokers: ALOT study.
Little is known about the long-term natural history of asthma and the long-term clinical and functional consequences in non-smoking patients. From a functional point of view, non-smoking asthmatic patients may have a significantly greater decline in forced expiratory volume in one second (FEV1) compared with non-asthmatic subjects and may develop chronic irreversible (fixed) airflow limitation. This has been related to the physiological consequences of chronic airway inflammation causing airway remodeling. However these lesions are all potentially reversible and there is little radiological evidence indicating lung destruction (pulmonary emphysema), which is potentially irreversible, in non-smoking asthmatics. Severe chronic respiratory failure is the major cause of mortality in patients with severe chronic lung diseases. Domiciliary long-term oxygen therapy (LTOT) is an accepted treatment for patients with severe chronic respiratory failure. Our reasoning, therefore, was that if asthma is a cause of severe chronic respiratory failure in non-smokers we should be able to find non-smoking asthmatics within a large population of patients on LTOT. The aim of our study (Asthma and Long-term Oxygen Therapy, "ALOT") was to investigate the prevalence of non-smoking asthmatics in patients on LTOT in a multi-centre, cross-sectional study. ⋯ This data suggests that asthma is an uncommon cause of severe chronic respiratory failure necessitating long-term domiciliary oxygen therapy in non-smokers and supports the current consensus that asthma and COPD are different diseases with differing stages of severity and the concept that long-term avoidance of active smoking is fundamental for the prevention of severe chronic respiratory failure.