A research method to induce and examine a mild exacerbation of asthma by withdrawal of inhaled corticosteroid
- 1 May 1992
- journal article
- Published by Wiley in Clinical and Experimental Allergy
- Vol. 22 (5), 525-532
- https://doi.org/10.1111/j.1365-2222.1992.tb00161.x
Abstract
This study evaluated a research method to examine an exacerbation of asthma induced by corticosteroid withdrawal. Ten non-smoking adult asthmatics who were stable on treatment with inhaled steroid underwent a graded reduction of the daily dose by 200 micrograms at weekly intervals until an exacerbation of symptoms occurred. A daily symptom, peak expiratory flow rate (PEF) and medication diary was kept. Weekly clinic visits were used to assess symptoms, spirometry, methacholine airway responsiveness (expressed as the provocative concentration to cause a fall in FEV1 of 20%, PC20), circulating eosinophils, basophils and their progenitors (Eo/B-CFU), and sputum inflammatory cells. The laboratory tests were performed blind to the clinical details. Each subject developed an exacerbation of symptoms, on average at 16 (7-26) days after the onset of steroid reduction. This was accompanied by a deterioration in each of the objective measures. There was a fall in FEV1 by 320 ml (s.e.m. 9.5) and in PC20 from 0.8 to 0.43 mg/ml. Circulating eosinophils rose from 114 (24) x 10(3)/ml to 227 (50) x 10(3)/ml and Eo/B-CFU rose from 31 (5.6) to 44 (11.3)/10(6) cells. Sputum developed in five subjects and contained 36 (5.2)% eosinophils and 1.98 (0.21)% metachromatic cells (mast cells or basophils). The symptom diary and weekly questionnaire were demonstrated to be valid and responsive to change. A deterioration indicated by the daily symptom score preceded changes in PEF. Treatment by an increase in steroid was followed by reversal of each of the changes.(ABSTRACT TRUNCATED AT 250 WORDS)Keywords
This publication has 19 references indexed in Scilit:
- Allergen-induced Asthmatic Responses: Relationship Between Increases in Airway Responsiveness and Increases in Circulating Eosinophils, Basophils, and Their ProgenitorsAmerican Review of Respiratory Disease, 1991
- Measurement of health status: Ascertaining the minimal clinically important differenceControlled Clinical Trials, 1989
- Cellular characteristics of sputum from patients with asthma and chronic bronchitis.Thorax, 1989
- Nonspecific Bronchial Reactivity and Its Relationship to the Clinical Expression of Asthma: A Longitudinal StudyAmerican Review of Respiratory Disease, 1989
- Measuring change over time: Assessing the usefulness of evaluative instrumentsJournal of Chronic Diseases, 1987
- Bronchoalveolar Neutrophilia during Late Asthmatic Reactions Induced by Toluene DiisocyanateAmerican Review of Respiratory Disease, 1987
- Comparative effects of inhaled salbutamol, sodium cromoglycate, and beclomethasone dipropionate on allergen-induced early asthmatic responses, late asthmatic responses, and increased bronchial responsiveness to histamine*1Journal of Allergy and Clinical Immunology, 1987
- A methodological framework for assessing health indicesJournal of Chronic Diseases, 1985
- Occupational asthma in snow crab-processing workersJournal of Allergy and Clinical Immunology, 1984
- Allergen‐induced increase in non‐allergic bronchial reactivityClinical and Experimental Allergy, 1977