Aspergillus sensitization is associated with airflow limitation and bronchiectasis in severe asthma.

BACKGROUND: Abnormalities, including bronchiectasis, that are detectable on high-resolution computed tomography (HRCT) have been associated with severe asthma. Bronchiectasis is associated with the diagnosis of allergic bronchopulmonary aspergillosis (ABPA), which also occurs in patients with severe asthma. We sought to determine the frequency and pattern of HRCT abnormality and the relationship with Aspergillus fumigatus sensitization in one severe asthma population. METHODS: We examined our database of patients attending a supraregional severe asthma service (Manchester, UK). Clinical, physiological and immunological characteristics were compared between those with HRCT evidence of airway disease (specifically bronchiectasis) and those with no radiological abnormality. RESULTS: Of 133 patients analysed, 111 (83.4%) had an abnormal HRCT with bronchial wall thickening (41.3%), bronchiectasis (35.3%), air trapping (20.3%) and bronchial dilatation (16.5%) occurring most frequently. Radiological evidence of airway disease was associated with more obstructive spirometry (postbronchodilator FEV1/FVC ratio 73.2%vs 64.8% [difference -8.5%, 95% CI -16.9 to -0.1, P = 0.048]). A. fumigatus sensitization was associated with a 2.01 increased hazard ratio of bronchiectasis (95% CI 1.26 to 3.22, P = 0.005), and more obstructive spirometry (postbronchodilator FEV1/FVC ratio 57.6 vs 70.3 [difference -12.8, 95% CI -19.8 to -5.7, P = 0.001]). Patients with A. fumigatus sensitization had variable clinical and radiological characteristics that frequently did not conform to the conventional diagnostic criteria for ABPA. CONCLUSION: Patients with severe asthma frequently have radiological abnormalities on HRCT. Sensitization to A. fumigatus is associated with bronchiectasis and greater airflow obstruction, even when diagnostic criteria for ABPA are not met.

Defining and investigating occupational asthma: a consensus approach.

BACKGROUND: At present there is no internationally agreed definition of occupational asthma and there is a lack of guidance regarding the resources that should be readily available to physicians running specialist occupational asthma services. AIMS: To agree a working definition of occupational asthma and to develop a framework of resources necessary to run a specialist occupational asthma clinic. METHOD: A modified RAND appropriateness method was used to gain a consensus of opinion from an expert panel of clinicians running specialist occupational asthma clinics in the UK. RESULTS: Consensus was reached over 10 terms defining occupational asthma including: occupational asthma is defined as asthma induced by exposure in the working environment to airborne dusts vapours or fumes, with or without pre-existing asthma; occupational asthma encompasses the terms "sensitiser-induced asthma" and "acute irritant-induced asthma" (reactive airways dysfunction syndrome (RADS)); acute irritant-induced asthma is a type of occupational asthma where there is no latency and no immunological sensitisation and should only be used when a single high exposure has occurred; and the term "work-related asthma" can be used to include occupational asthma, acute irritant-induced asthma (RADS) and aggravation of pre-existing asthma. Disagreement arose on whether low dose irritant-induced asthma existed, but the panel agreed that if it did exist they would include it in the definition of "work-related asthma". The panel agreed on a set of 18 resources which should be available to a specialist occupational asthma service. These included pre-bronchodilator FEV1 and FVC (% predicted); peak flow monitoring (and plotting of results, OASYS II analysis); non-specific provocation challenge in the laboratory and specific IgE to a wide variety of occupational agents. CONCLUSION: It is hoped that the outcome of this process will improve uniformity of definition and investigation of occupational asthma across the UK.

Defining and investigating difficult asthma: developing quality indicators.

BACKGROUND: There is no agreed definition of 'difficult asthma' or what investigations should be available to investigate these patients. Patients with difficult asthma remain symptomatic on high levels of treatment and are high users of medical resources. AIM: To develop a set of quality indicators for the definition and investigation of difficult asthma. METHOD: Modified RAND Appropriateness Method was used. An expert panel composed of nine hospital asthma specialists who run 'difficult' asthma clinics and were identified from a short list of key workers in the field. Indicators were rated as necessary to define and investigate difficult asthma. RESULTS: Difficult asthma was defined as 'symptoms persisting beyond therapy consistent with step 4 of the British Thoracic Society (BTS) guidelines' (high dose inhaled corticosteroids and long acting beta(2)-agonists). Eighty-three indicators were identified (40 relating to definition and 43 relating to investigations). Of these 32 (39%) were rated as necessary: 7 out of 40 (18%) for defining difficult asthma and 23 out of 43 (53%) for investigations. Indicators of high medical resource usage were characteristic of the 'difficult' nature of the management of patient with difficult asthma. A framework for the investigation of these patients was created. CONCLUSION: The listed performance indicators identify a range of requirements that are necessary to define difficult asthma. Targeting of real needs in this group of patients will lead to better patient care and reduction of 'waste' in provision of healthcare.