AIRWAYS HYPERRESPONSIVENESS, BRONCHODILATOR RESPONSE, ALLERGY AND SMOKING PREDICT IMPROVEMENT IN FEV(1) DURING LONG-TERM INHALED CORTICOSTEROID TREATMENT

Airways hyperresponsiveness, bronclwdilator response, allergy and smoking predict im­ provement in FEV 1 during long-tenn inhaled corticosteroid treatment. H.A.M. Kerstjens, S.E. Overbeek, J.P. Schouten, P.L.P. Brand, D.S. Postma, and the Dutch CNSLD Study Group. ©ERS JouT7UJis Ltd 1993. ABSTRACT: Although most patients with obstructive airways disease show some amelioration with long-term inhaled corticosteroid therapy, the extent or improve­ ment may vary considerably between patients. Patients with mild to moderately severe obstructive airways disease (asthma and COPD) were selected if provocative concentration producing a 20% faU in forced expiratory volu.in one second (PCzo) ~ mg·mJ·•, and forced expiratory volume in one second (FEV 1 ) <95% confidence intervals (Cl) of predicted normal. The independent influences of baseline PC 20 FEV" inspiratory vital capacity (IVC), bron­ chodilator response, smoking habits, and aUergy both on the "immediate" (within 3 months) response in FEV1 and the change in long-term (from 3 months onwards) slope of FEV1 with inhaled corticosteroids were analysed. Patients bad a larger "immediate" improvement in their FEV 1 with inhaled corticosteroids with each doubling doses lower PC 10 , with each ten-fold higher im­ munoglobulin E (IgE), and if they did not smoke. Total IgE proved a better inde­ pendent predictor of "immediate" response than specific lgE for house dust mite, skin tests, or blood eosinophils. A more favourable long-term slope of FEV1 was predicted by a larger baseline bronchodilator response, but not by smoking. In conclusion, PC 20 , total lgE, and smoking habits are independent predictors of immediate treatment response to inhaled corticosteroids. Bronchodilator response is the single independent predictor of changes in long-term slope of FEV 1 with cor­ ticosteroid treatment.