House dust mite control measures for asthma

 

Abstract

Background

The major allergen in house dust comes from mites. Chemical, physical and combined methods of reducing mite allergen levels are intended to reduce asthma symptoms in people who are sensitive to house dust mites.

Objectives

To assess the effects of reducing exposure to house dust mite antigens in the homes of people with mite-sensitive asthma.

Search methods

We searched PubMed and the Cochrane Airways Group Register (last search July 2011). No restrictions were placed on language of publication.

Selection criteria

We included randomised trials of mite control measures versus placebo or no treatment in people with asthma known to be sensitive to house dust mites.

Data collection and analysis

Two authors applied the trial inclusion criteria and evaluated the data. We contacted trial authors to clarify information.

Main results

We included 55 trials (3121 patients). Thirty-seven trials assessed physical methods, including 26 trials employing mattress encasings. Ten trials involved chemical methods and eight trials involved a combination of chemical and physical methods. Despite the fact that many trials were of poor quality and would be expected to exaggerate the reported effect, we did not find an effect of the interventions. For the most frequently reported outcome, peak flow in the morning (1665 patients), the standardised mean difference (SMD) was 0.01 (95% confidence interval (CI) -0.08 to 0.11). There were no statistically significant differences either in number of patients improved (risk ratio 1.01, 95% CI 0.80 to 1.27), asthma symptom scores (SMD -0.06, 95% CI -0.16 to 0.05), or in medication usage (SMD -0.05, 95% CI -0.17 to 0.07).

Authors' conclusions

Chemical and physical methods aimed at reducing exposure to house dust mite allergens cannot be recommended. It is doubtful whether further studies, similar to the ones in our review, are worthwhile. If other types of studies are considered, they should be methodologically rigorous and use other methods than those used so far, with careful monitoring of mite exposure and relevant clinical outcomes.

 

Plain language summary

Does controlling exposure to house dust mites improve asthma?

Asthma is a chronic inflammatory disease of the airways. The prevalence of asthma has increased and it is now the commonest chronic disease among children. Asthma is triggered by allergens (substances that cause an allergic reaction) and house dust presents a problem in some people with asthma. The major allergen in house dust comes from mites and it is hypothesised that controlling exposure to house dust mites will reduce asthma symptoms in people who are sensitive to house dust mites.

We included 55 randomised trials on 3121 people with asthma. There are both chemical (10 trials) and physical methods such as mattress encasings (37 trials) of reducing mite allergen levels and we included both types in this review. There were also eight trials that used both physical and chemical methods. Many trials were of poor quality and would therefore be expected to exaggerate the reported effect, but we did not find an effect of the interventions. There was no difference in peak flow (a measure of lung function), asthma symptoms and medication scores, or the number of patients reporting an improvement in their asthma symptoms.

While reducing exposure to house dust mites is recommended in guidelines, we did not find an effect of control measures to reduce the exposure to mites or their products. .

 

摘要

背景

針對氣喘的家戶塵(虫滿)控制量測

房中灰塵中的主要過敏原主要是來自塵(虫滿)。利用化學，物理和混合的方法以降低塵(虫滿)過敏原層級的目的是為了減少對房子內塵(虫滿)過敏的人的氣喘症狀。

目標

為了評估在塵(虫滿)過敏性氣喘患者家中減少接觸室內塵(虫滿)抗原所產生的影響。

搜尋策略

Cochrane Airways Group trials register及PubMed和The Cochrane Library(最近一次於於2004年1月檢索)和參考文獻列表。

選擇標準

對已知的對屋內塵(虫滿)過敏的氣喘病患採取塵(虫滿)控制監測或安慰劑治療或不治療的隨機試驗，。

資料收集與分析

兩名審查員獨立的設立了試驗納入標準，評估試驗品質和分析數據。聯繫了研究的作者以確定資訊。

主要結論

涵括了49個試驗(2733名病患)：病人人數比上一次審查時增加了多過一倍。31個試驗評估物理方法，10個試驗評估和8個試驗評估化學和物理混合的方法。儘管許多試驗品質不佳而且預期會誇大其試驗的結果，但我們並沒有發現到干預措施是有影響的。對於最常見的結果，在早上的尖峰呼吸流量(1339例)，其平均標準差為−0.02(95％信賴區間(CI)−0.13到0.08)。無論在有改善的病人數量(相對風險1.01，95％CI為 0.80～1.27)、氣喘症狀評分(標準化平均差−0.01，95％CI為 −0.10到0.13)，或於藥物使用比率(標準化平均差0.05，95％CI為 −0.18～0.09)都沒有統計學上的顯著差異。

作者結論

無法建議利用化學和物理方法來降低接觸室內塵(虫滿)過敏原。是否值得進一步的研究是令人懷疑，類似於我們的後設分析中的試驗。如果考量其他類型的研究，應於方法學上更為嚴格並使用其他和目前使用不同的方法來認真監測暴露於塵(虫滿)環境中和其相關臨床結果。

翻譯人

本摘要由臺北醫學大學萬芳醫院劉怡敏翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

利用化學和物理方法以降低塵(虫滿)過敏原的層級似乎對氣喘病患缺乏效果。房中灰塵中的主要過敏原主要是來自塵(虫滿)。利用化學，物理和混合的方法以降低塵(虫滿)過敏原層級的目的是為了減少對房子內塵(虫滿)過敏的人的氣喘症狀。此次審查並沒有發現減少接觸塵(虫滿)或其產品的控制監測是會造成影響的。