Bale 1998.
| Methods | A single‐centre, prospective, parallel‐group RCT with 100 participants Conducted in the UK Follow‐up: 8 weeks Participants recruited from the community over 10 month period from 26 April 1993 with the last follow‐up visit completed on 13 June 1994. No other specific details provided | |
| Participants |
Inclusion criteria: judgement by investigator if treatment with study dressings was appropriate, leg ulcers of any aetiology except those with venous ulceration who were able to tolerate compression therapy, and those with Stage II and III sore (classified using an early version of the NPUAP), or other granulating wounds with moderate‐high levels of exudate Exclusion criteria: pregnant or lactating women, people with pressure sores classified Stage I or Stage IV (classified using an early version of the NPUAP), wound expected to heal within 1 week or wound with sloughy or necrotic tissue or grossly infected wound (although these people could be included in the study after the wound had been debrided or the infection had been resolved) If a participant presented with more than one suitable wound, data on the largest wound was collected during the study period In the hydrocellular foam dressing group at baseline (n = 50) from combined data of wound types, PUs, leg ulcers and other
In the hydrocolloid dressing group at baseline (n = 46) from combined data of wound types, PUs, leg ulcers and other
Ethcial approval reported as being obtained, and written consent from participants obtained |
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| Interventions | Group A: hydrocellular dressing (Allevyn) until the wound healed, or for a maximum of 8 weeks (n = 50, of which PU n = 17) Group B: hydrocolloid dressing (Granuflex) until the wound healed, or for a maximum of 8 weeks (n = 46, of which PU n = 15) | |
| Outcomes |
Primary outcomes Adverse events per participant (data not separated by wound type) Secondary outcomes Reduction in ulcer size (data not separated by wound type) Patient satisfaction/acceptability (data not separated by wound type) Economic outcomes Cost and incremental cost per event (total costs of study materials and cost effectiveness per participant) |
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| Notes | Missing data/exclusions: "Four patients have been excluded from the efficacy, performance and economic analysis." 21/49 (43%) of participants in Group B (hydrocolloid dressing) were withdrawn from the study before completion compared to 10/51 (20%) of participants in Group A (hydrocellular foam dressing). However, it is unclear what proportion of those participants with PUs were withdrawn from the study Wounds treated in Group A (hydrocellular foam dressing) were significantly larger than those treated in Group B (hydrocolloid dressing) Study funded by Smith & Nephew, manufacturer of Allevyn |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quotation: "...subjects were randomised in blocks of four to Group A, to receive the hydrocellular dressing (Allevyn) or to Group B, to receive the hydrocolloid dressing (Granuflex)." Comment: no indication of how randomisation was achieved |
| Allocation concealment (selection bias) | Unclear risk | Quotation: "...subjects were randomised in blocks of four to Group A, to receive the hydrocellular dressing (Allevyn) or to Group B, to receive the hydrocolloid dressing (Granuflex)." Comment: no indication if allocation was concealed |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | Quotation: "All patients in the trial were treated by research nurses from the Wound Healing Research Unit in accordance with the study protocol." Comment: unclear if participants and personnel were blinded to group allocation |
| Blinding of outcome assessment (detection bias) All outcomes | High risk | Quotation: "It must be noted that one of the problems of collecting subjective data when it is not a blind assessment is the introduction of unconscious bias." Comment: suggests that those assessing the wounds were not blinded to the intervention |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Quotation: "Four patients have been excluded from the efficacy, performance and economic analysis. One patient in Group A (hydrocellular foam dressing) had a wound which was too large. In Group B (hydrocolloid dressing), two patients were withdrawn from the study within seven days and a third died during the study and the case report form was not recovered. All other patients recruited (including later withdrawals) have been incorporated in all statistical analyses; 43% of patients were withdrawn after the initial; seven days in Group B compared to 20% in Group A. Thus the difference was statistically significant ( p = 0.012, x 2 = 6.32, df = 1)." Comment: it appears that all 32 participating in the PU subgroup were included in the analysis. Only 4 participants were excluded for the larger combined group as described above |
| Selective reporting (reporting bias) | Unclear risk | No direct quotation addressing this aspect Comment: limited information on which to judge |
| Other bias | High risk | Comment: Subgroup analyses undertaken in only part of the trial population Quotation: “Wounds treated in Group A when the study commenced were significantly larger than those treated in Group B (median 4.7cm2 (p=0.037)." Comment: dissimilarity of study groups may be a source of bias, although group A (hydrocellular foam dressing) were reported as having better outcomes at 56 days than the hydrocolloid dressing |