NEW YORK (Reuters Health) - Neither the most labor-intensive nor the most costly interventions to rid a residence of dust mite allergens have any effect on the symptoms of asthma patients who are sensitive to house dust mites, according to a large analysis of clinical trials by researchers in Denmark.
"Chemical and physical methods aimed at reducing exposure to house dust mite allergens cannot be recommended," Dr. Peter Gotzsche, Director of The Nordic Cochrane Centre in Copenhagen and Dr. H. K. Johansen at the University of Copenhagen state in the Cochrane Database of Systematic Reviews.
The researchers searched PubMed and The Cochrane Library for randomized trials of mite control measures versus placebo or no treatment in the houses of people with asthma who were sensitive to these little bugs. Their review included 54 trials involving 3,002 patients.
Ten trials used chemical methods, 36 used physical methods (including mattress covers, vacuum-cleaning, heating, ventilation, freezing, washing, air-filtration and ionizers), and 8 used a combination of physical and chemical methods. The length of the intervention and follow-up varied from 2 weeks to 2 years.
Reports for 17 trials indicated that mite reduction had occurred, while 24 reported that reduction was unsuccessful, and 13 made no mention of this outcome.
"We were unable to demonstrate any clinical benefit ... of measures designed to reduce mite exposure," the authors write. Specifically, none of the interventions significantly improved study participants' asthma symptom scores, medication usage, or peak respiratory flow in the morning.
""We can conclude with confidence that there is no need to buy expensive vacuum cleaners or mattress covers or to use chemical methods against house dust because we know these treatments do not work," Gotzsche commented in a written statement.
He has seen $10,000 vacuum cleaners marketed to vulnerable parents of children with asthma. These machines don't even work as well as cheap vacuum cleaners, he added.
