| Methods |
Design: three group parallel trial
Purpose: examine the effect of a back school treatment program and placebo intervention on chronic low back pain |
| Participants |
Patients: out‐patients with chronic low back pain
Baseline comparability: yes |
| Interventions |
Placebo: sessions of transcutaneous electrical nerve stimulation (TENS) with the TENS machine off
Untreated: no sessions
Experimental: sessions of the 'Interactional Back School' Program
(Co‐intervention: NS) |
| Outcomes |
Pain (VAS) |
| Notes |
Standard deviation of 10 cm visual analogue pain scales, pain 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 |
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? |
High risk |
N = 28 |
| Clearly concealed allocation + trial size > 49 + drop‐out max 15% |
High risk |
Trial size < 49 |
