Recer G M
New York State Department of Health, Center for Environmental Health, Troy, NY 12180, USA.
Clin Exp Allergy. 2004 Feb;34(2):268-75. doi: 10.1111/j.1365-2222.2004.01863.x.
Sensitization and exposure to dust-mite antigens are causative factors in the development and exacerbation of asthma. Impermeable bedding encasements are considered a first-line treatment to reduce dust-mite antigen exposure in clinical asthma-management guidelines. Public-health recommendations for environmental asthma treatments should be based on the weight of evidence supporting the reliability of environmental interventions so that uncertainties regarding their effectiveness can be accurately communicated to patients, and so that limited public-health resources can be most effectively utilized.
To evaluate the strength of a clinical-trial evidence supporting the efficacy of bedding encasements as an asthma treatment.
A narrative review was conducted of all clinical trials involving bedding encasement for the treatment of asthma. Collective statistical analyses were also performed to characterize the quantitative effect of bedding encasement on dust-mite allergen exposure and bronchial hyper-responsiveness (BHR) when used by asthma patients.
Over 30 clinical trials were reviewed. Of those studies reporting adequate exposure and BHR results, four reported significant reduction in dust-mite allergen exposure and concomitant BHR reduction in active-treatment groups using bedding encasements. In 10 studies, mite-allergen exposure was reportedly decreased during the study, but BHR was not changed in the active-treatment group or was reduced to a similar degree in the active-treatment and control groups. Five other studies reported a lack of significant effect of the intervention on exposure and BHR. Collective paired analyses found that the effect of bedding encasement on allergen exposure and BHR tended toward only a modest, non-significant improvement. Collectively, effects of bedding encasement on BHR and dust-mite allergen exposure were modestly correlated only when the baseline exposure was above 2 microg Type 1 antigen per gram settled dust.
Although bedding encasement might be an effective asthma treatment under some conditions, when implemented in clinical trials by asthma patients, its effectiveness is inconsistent and appears to be, at best, modest. Therefore, its significance as a reliable asthma management modality for any individual asthma patient is uncertain. Where resource constraints are significant, targeting the use of variably effective interventions such as bedding encasements toward those patient sub-populations most likely to derive substantial benefit may gain the largest net public-health benefit.
对尘螨抗原的致敏和接触是哮喘发生及加重的致病因素。在临床哮喘管理指南中，不可渗透的床上用品保护套被视为减少尘螨抗原接触的一线治疗方法。关于环境性哮喘治疗的公共卫生建议应基于支持环境干预可靠性的证据权重，以便能够将其有效性的不确定性准确传达给患者，并最有效地利用有限的公共卫生资源。
评估支持床上用品保护套作为哮喘治疗方法有效性的临床试验证据的力度。
对所有涉及使用床上用品保护套治疗哮喘的临床试验进行叙述性综述。还进行了汇总统计分析，以描述哮喘患者使用床上用品保护套时对尘螨过敏原接触和支气管高反应性（BHR）的定量影响。
审查了30多项临床试验。在那些报告了充分的接触和BHR结果的研究中，有四项报告称，使用床上用品保护套的积极治疗组中，尘螨过敏原接触显著减少，同时BHR也降低。在10项研究中，据报道在研究期间螨过敏原接触减少，但积极治疗组的BHR没有变化，或者在积极治疗组和对照组中降低到相似程度。其他五项研究报告称，该干预措施对接触和BHR没有显著影响。汇总配对分析发现，床上用品保护套对过敏原接触和BHR的影响仅倾向于适度的、不显著的改善。总体而言，只有当基线接触量高于每克沉降灰尘2微克1型抗原时，床上用品保护套对BHR和尘螨过敏原接触的影响才存在适度相关性。
尽管床上用品保护套在某些情况下可能是一种有效的哮喘治疗方法，但哮喘患者在临床试验中使用时，其有效性并不一致，充其量似乎只是适度有效。因此，其作为任何个体哮喘患者可靠的哮喘管理方式的意义尚不确定。在资源限制显著的情况下，将床上用品保护套等效果不一的干预措施针对最有可能从中获得实质性益处的患者亚群使用，可能会获得最大的公共卫生净效益。
