Burr 2007.
| Methods | RCT | |
| Participants | Participants aged 3 to 61 who reported symptoms of asthma in the last 12 months and indoor mould in 81 intervention houses (115 persons) and 83 control houses (117 persons) in South Wales | |
| Interventions | Removal of all visible mould and fungicide treatment in mould‐damaged houses. A positive input fan was also installed in damaged houses | |
| Outcomes | Buildings ‐ Primary: presence of visible indoor mould Secondary: temperature and humidity Patients ‐ Primary: variability in peak expiratory flow rate Secondary: perceived improvement in breathing, reported change in medication use, wheezing and symptoms of rhinitis and rhinoconjunctivitis |
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| Notes | The intervention was only partially successful, because by 12 months mould was present in 40% of the intervention houses and 78% of the control houses | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | Not done |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Probably not done |
| Unplanned subgroup analyses (16) | Low risk | No unplanned subgroup analyses |
| Follow‐up (17) | Low risk | Follow‐up time 12 months |
| Compliance (19) | Unclear risk | "Some members of the control group took their own action to remove mould so that by 12 months it was present in only 78% of control houses" |
| Valid outcome measures (20) | Unclear risk | Subjective symptoms and changes in asthma medication |
| Selection bias (population) (21) | Low risk | Both participants and controls were recruited from the same population |
| Selection bias (time) (22) | Low risk | The questionnaires were sent to both the intervention and control group at the same time |
| Random sequence generation (selection bias) | Low risk | The houses were randomised |
| Allocation concealment (selection bias) | Unclear risk | Not reported |
| Adjustment for confounding (25) | Unclear risk | Only mean age and number of current smokers were reported |
| Incomplete outcome data (26) (attrition bias) | Low risk | The numbers of houses and persons lost to follow‐up were reported |