| Methods |
Design: three group parallel trial
Purpose: study the effect of applied muscle tension on blood donation reactions |
| Participants |
Patients: English speaking blood donors
Baseline comparability: yes (age, gender) |
| Interventions |
Placebo: applied muscle tension training for 2 minutes
Untreated: no training
Experimental: applied muscle tension training for 15 minutes
(Co‐intervention: no) |
| Outcomes |
Blood donations reactions inventory score
Proportion of cases in which donation chairs were reclined
Proportion of full blood portion donated
Doner's estimate of the probability of giving blood again
Pain
Anxiety
Heart rate
Blood pressure |
| Notes |
Trialists assumed that at least 5 minutes of applied muscle tension training was needed for an effect. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Adequate sequence generation? |
Unclear risk |
NS |
| Allocation concealment? |
Unclear risk |
NS |
| Blinding?
Treatment provider |
High risk |
Not described as double‐blind (placebo/applied muscle tension) |
| Blinding?
Outcome assessor |
Unclear risk |
Not relevant as patient reported outcome |
| 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? |
Low risk |
|
| No signs of variance inequality or skewness? |
High risk |
Either variance inequality (F‐test statistically significant) or skewness (1.64 standard deviations exceeds the mean) |
| Trial size > 49? |
Low risk |
N = 389 |
| Clearly concealed allocation + trial size > 49 + drop‐out max 15% |
High risk |
Drop‐out > 15% or NS |
