| Methods |
Design: three group parallel trial
Purpose: examine the effect of cognitive‐behavioural intervention, and placebo, on pain associated with sickle cell disease |
| Participants |
Patients: out‐patients with sickle cell disease (type HbSS)
Baseline comparability: yes (age, gender, hospital admissions for painful crises, etc) |
| Interventions |
Placebo: one hourly session per week for two months of general discussions of the problems of living with sickle cell disease (attention‐placebo)
Untreated: no sessions
Experimental: sessions of cognitive‐behavioural therapy
(Co‐intervention: NS) |
| Outcomes |
Pain (Short form of McGill pain questionnaire)
General health questionnaire
Coping strategies questionnaire
Pain self‐efficacy questionnaire
Beliefs about pain control questionnaire
Number of hospital and emergency admissions
Duration of hospital stay |
| Notes |
The result is probably unreliable because 38 of 97 patients dropped out (39%). In addition, 23 of 56 patients treated with placebo or active sessions were excluded because of failure to attend sessions or to complete assessments, no such exclusions described for no‐treatment group. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Adequate sequence generation? |
Low risk |
'random number table and was restricted to blocks of four ...' |
| Allocation concealment? |
Unclear risk |
'a sequence of labeled cards contained in sealed numbered envelopes' |
| Blinding?
Treatment provider |
High risk |
Not described as double‐blind (cognitive‐behavioural intervention/placebo) |
| Blinding?
Outcome assessor |
Unclear risk |
Not relevant as patient reported outcome |
| Incomplete outcome data addressed?
All outcomes |
High risk |
Drop‐out > 15%. The result is probably unreliable because 38 of 97 patients dropped out (39%). In addition, 23 of 56 patients treated with placebo or active sessions were excluded because of failure to attend sessions or to complete assessments, no such exclusions described for no‐treatment group. |
| 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 = 40 |
| Clearly concealed allocation + trial size > 49 + drop‐out max 15% |
High risk |
Trial size < 49 |
