| Methods |
Randomised, cross‐over double blind placebo controlled trial. Participants recruited from pulmonology outpatient clinic in Groningen. |
| Participants |
Children (N = 22, M = 8) were recruited but two withdrew from the study. Moderate asthmatics with a cat or dog at home, all were responsive to adenosine monophosphate, no URTIs during the course of the study. |
| Interventions |
Active versus sham (placebo) air filtration units. Phillips air cleaner in the living room and bedroom, over a 6 month period (3 month treatment arm, no wash out period). |
| Outcomes |
Airways hyperresponsiveness to adenosine, FEV1 % predicted value, peak flow, medication and symptoms. |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Adequate sequence generation? |
Low risk |
Minimisation method |
| Allocation concealment? |
Unclear risk |
Information not available |
| Blinding?
All outcomes |
Low risk |
Sham filter unit used. |
| Free of other bias? |
High risk |
The participants were described as having minimal symptoms when using inhaled steroids, and a high an FEV1, implying that they were well controlled and suffering from only very mild asthma. It was felt that this may inhibit the demonstration of a clear treatment effect. The exclusion of participants who changed medication during the study also made it impossible to detect an effect on medication usage. |
