| Methods |
Design: three group, three period cross‐over trial
Purpose: to examine the effect of placebo on exercise induced asthma |
| Participants |
Patients: children with bronchial asthma
Baseline comparability: not relevant |
| Interventions |
Placebo (according to active drug):
‐injections of saline
‐inhalations of saline
‐inhalations of lactose with sodium sulphate
Untreated: no injections or inhalations
Experimental:
‐inhalations of salbutamol
‐injections of atropine
‐inhalation of cromoglycate
(Co‐intervention: NS) |
| Outcomes |
Fall in % peak expiratory flow (PEF) rate
Number of patients with a drop in PEF rate of at least 15% |
| Notes |
Data originally came from three small cross‐over trials. The outcome data was not available from the first period only, and was calculated as deriving from one parallel group trial. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Adequate sequence generation? |
Unclear risk |
NS |
| Allocation concealment? |
Unclear risk |
NS |
| Blinding?
Treatment provider |
Unclear risk |
NS |
| Blinding?
Outcome assessor |
Unclear risk |
NS |
| Incomplete outcome data addressed?
All outcomes |
High risk |
Drop‐out > 15 % or NS |
| Free of selective reporting? |
Unclear risk |
No protocol available |
| Free of other bias? |
High risk |
Data originally came from three small cross‐over trials. The outcome data was not available from the first period only, and was calculated as deriving from one parallel group trial. |
| No signs of variance inequality or skewness? |
Unclear risk |
Not relevant (not naturally positive continuous outcomes e.g. change) |
| Trial size > 49? |
Low risk |
N = 88 |
| Clearly concealed allocation + trial size > 49 + drop‐out max 15% |
High risk |
Drop‐out > 15 % or NS |
