| Methods |
Design: three group parallel trial
Purpose: examine the effect of transcutaneous electrical nerve stimulation (TENS) on pain |
| Participants |
Patients: persons having a venepuncture to give blood
Baseline comparability: yes |
| Interventions |
Placebo: placebo TENS
Untreated: no TENS or placebo TENS
Experimental: TENS
(Co‐intervention: NS) |
| Outcomes |
Pain (VAS) |
| Notes |
Standard deviation of 10 cm visual analogue pain scale, means calculated from F‐test statistic. |
| 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 |
Not relevant as patient reported outcome |
| Incomplete outcome data addressed?
All outcomes |
Low risk |
Drop‐out < 15% |
| 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? |
High risk |
N = 42 |
| Clearly concealed allocation + trial size > 49 + drop‐out max 15% |
High risk |
Trial size < 49 |
