COMPARISON OF INHALED CORTICOSTERIOD, LONG LASTING BETA AGONIST, AND PLACEBO

受体激动剂是非常有效的支气管扩张剂，已被广泛用于哮喘患者的一线治疗。然而，最近的研究表明，长期定期使用可能会导致哮喘控制恶化或增加哮喘死亡或接近死亡的风险。推测支气管扩张可能允许持续暴露于抗原和其他引起炎症的物质，或者因为活性剂刺激炎症。美国国家心脏、肺和血液研究所（NHLBI）哮喘管理专家小组建议，吸入-受体激动剂继续用于缓解症状，但对每天需要-受体激动剂的患者应进行抗炎治疗。吸入皮质类固醇是慢性治疗中最常用的抗炎药。尽管越来越多地使用高剂量吸入性皮质类固醇治疗引起了人们对长期使用可能产生不良反应的担忧，但吸入标准剂量的皮质类固醇似乎是安全有效的。受体激动剂被认为可以缓解症状，而吸入皮质类固醇被认为可以改变疾病；有证据表明，即使在减少或停止吸入皮质类固醇（药物效应）后，哮喘也能得到控制。沙美特罗是一种长效吸入β激动剂，可诱导支气管扩张，并可能具有抗炎特性。虽然早期对定期使用沙美特罗的研究表明，它可以减轻哮喘症状的严重程度，但其支气管扩张与抗炎作用的重要性尚不清楚。通过研究治疗结束时炎症标志物的减少与治疗结束后症状复发率（停药效应）之间的关系，可以推断出抗炎与支气管扩张活性的相对重要性。使用仅具有支气管扩张剂特性的药物治疗后，比使用改变疾病基本发病机制的药物治疗后，症状更容易迅速复发。在中度哮喘患者中，本研究将测试单独吸入皮质类固醇、单独吸入长效β受体激动剂或安慰剂在控制哮喘症状和气道功能方面是否更有效。

Beta-agonists are extremely effective as bronchodilators and have been widely used as first line therapy for people with asthma. However, recent studies suggest that long term regular use may contribute to worsening asthma control or increase the risk of death or near death from asthma. Speculation is that bronchodilation may permit continued exposure to antigens and other material that provoke inflammation or because the active agent stimulates inflammation. The National Heart, Lung and Blood Institute's (NHLBI's) Expert Panel on the Management of Asthma recommends that inhaled beta-agonists continue to be used as required for the relief of symptoms, but that anti-inflammatory therapy be instituted in patients who require beta-agonists on a daily basis. Inhaled corticosteroids are the most commonly used anti-inflammatory agents used for chronic therapy. Although increasing use of high-dose inhaled corticosteroid therapy has raised concerns about the potential for adverse effects with long-term use, standard doses of corticosteroids given by inhalation appear to be safe and effect. Beta-agonists are felt to provide symptom relief while inhaled corticosteroids are felt to modify the disease; there is evidence of asthma control even after inhaled corticosteroids are reduced or stopped (off drug effect). A long-acting inhaled beta-agonist, salmeterol induces bronchodilation and may have anti-inflammatory properties. While early studies of the regular use of salmeterol suggest that it reduces the symptomatic severity of asthma, the importance of its bronchodilating versus anti-inflammatory activities is not known. The relative importance of anti-inflammatory versus bronchodilation activity might be inferred by studying the relationship between reductions in inflammatory markers at the completion of the therapy and the rate of recurrence of symptoms after therapy is removed (off drug effect). Symptoms are more likely to recur quickly after therapy with agents having only bronchodilator properties than after therapy with agents that alter the fundamental pathogenesis of the disease. This study will test, in patients with moderate asthma, whether inhaled corticosteroids alone or inhaled long-acting beta-agonist alone or placebo is more efficacious in controlling asthma symptoms and airway function.