Armstrong 1997

Number of ulcers healed at 6 weeks:

Group 1 (hydrocolloid dressing):  6/21 (29%)

Group 2 (alginate dressing):  2/23 (9%)

P value for between‐group difference not reported. 

Change in ulcer size – median change in area:

Group 1 (hydrocolloid dressing):  ‐205 mm²

Group 2 (alginate dressing):  ‐162 mm²

The trial authors reported that the between‐group difference was not statistically significant. P value not reported. 

Change in ulcer size – median percentage change in ulcer area:

Group 1 (hydrocolloid dressing):  ‐42%

Group 2 (alginate dressing):  ‐26%

The trial authors reported that the between‐group difference was not statistically significant. P value not reported. Review authors' comment: there was a reporting discrepancy between primary and secondary references for this outcome. The respective values in the secondary reference were ‐30.5% and ‐28.1%.

Harding 2001

Time to healing days ‐ mean (SD) [median (range)] (analysis based on healed participants only):

Group 1 (hydrocolloid dressing):  41.823 days (SD 21.302) [42 (14 to 87)]; n = 17

Group 2 (alginate dressing):  56.588 days (SD 21.569) [56 (14 to 85)]; n = 17

Reported P value for between‐group difference in means = 0.053

P = 0.05 (log rank test) for difference in Kaplan‐Meier survival curves (analysis based on all randomised patients) 

Number of ulcers healed at 12 weeks:

Group 1 (hydrocolloid dressing): 17/66 (26%)

Group 2 (alginate dressing): 17/65 (26%)

P value for between‐group difference not reported 

Change in ulcer area mm² ‐ mean (SD) [median (range)]:

Group 1 (hydrocolloid dressing):  ‐516.86 mm² (SD 1202.72) [‐301.13 (‐2494.84 to 5285.82)]; n = 66

Group 2 (alginate dressing):  ‐347.30 mm² (SD 1382.69) [‐132.83 (‐5144.08 to 5946.24)]; n = 65

P value for between‐group difference in means P = 0.48, reported by trial authors.

Percentage change in ulcer area – mean (SD) [median (range)]:

Group 1 (hydrocolloid dressing):  ‐38.18% (SD 92.36) [‐67.67 (374.84 to ‐100.00)]; n = 66

Group 2 (alginate dressing):  ‐30.54% (SD 84.08) [‐43.33 (411.74 to ‐100.00)]; n = 65

P value for between‐group difference in means = 0.64, reported by trial authors

Límová 2003

Number of ulcers healed at 6 weeks:

Group 1 (alginate dressing, Tegagen ™ HG): 0/11 (0%)

Group 2 (alginate dressing, Sorbsan®): 2/9 (22%)

P value for between‐group difference not reported.

Mean percentage change in wound area at 6 weeks:

Group 1 (alginate dressing, Tegagen ™ HG):  ‐33.7%, n = 10

Group 2 (alginate dressing, Sorbsan®):  ‐29.6%, n = 9

The trial authors reported a P value of 0.88 for between‐group difference

Moffatt 1992

Time to healing/number of ulcers healed at 12 weeks:

Group 1 (plain non‐adherent dressing): 24/30 (80%)

Group 2 (alginate dressing): 26/30 (87%)

P value for between‐group difference not reported

The trial authors reported that results were similar for cumulative proportions healed estimated using life table analysis (no data or P value for between‐group difference presented)

Smith 1994

Number of ulcers healed at 6 weeks:

Group 1 (hydrocolloid dressing): 4/22 (18%)

Group 2 (alginate dressing): 2/18 (11%)

P value for between‐group difference not reported 

Mean percentage change in ulcer area:

Group 1 (hydrocolloid dressing):  ‐57.1

Group 2 (alginate dressing): ‐34.9

The trial authors reported that the between‐group difference was not statistically different. P value not reported

Armstrong 1997

Mean wear time days:

Group 1 (hydrocolloid dressing):  4.112 days

Group 2 (alginate dressing):  3.051 days

The trial authors reported a between‐group difference of 1.029 days (95% CI 0.385 to 1.672), and that the difference was statistically significant in favour of Group 1 but the P value was not reported. Reviewer authors' comment: the difference in means reported by the trial authors does not follow from the mean values for each group 

Number participants achieving a 7‐day wear time on at least one occasion:

Group 1 (hydrocolloid dressing):  9/21 (43%)

Group 2 (alginate dressing):  3/23 (13%)

The trial authors reported that the between‐group difference (30%, 95% CI 5% to 55%) was statistically significant but P value not reported 

Cost to heal one ulcer:

Group 1 (hydrocolloid dressing):  GBP 237.66 (total direct and indirect costs = GBP 1425.97 for total of 6 wounds healed)

Group 2 (alginate dressing):  GBP 687.31 (total direct and indirect costs = GBP 1374.61 for total of 2 wounds healed)

Cost per wound healed calculated by review authors.

Taking into account the number of participants completely healed in each group, the trial authors reported that the cost to achieve a healed wound using the Group 1 dressing was approximately one‐third of the cost of Group 2. 

Number dressing changes with no pain, mild pain, moderate pain, severe pain, excruciating pain, unable to respond, missing data:

Group 1 (hydrocolloid dressing):  (total of 192 dressing changes) 144 (75%), 38 (20%), 6 (3%), 2 (1%), 0 (0%), 0 (0%), 2 (1%)

Group 2 (alginate dressing):  (total of 224 dressing changes) 186 (83%), 29 (13%), 8 (3.5%), 0 (0%), 0 (0)%, 0 (0%), 1 (0.5%) 

Number of adverse events during the trial:

Group 1 (hydrocolloid dressing): 32 adverse events reported during the trial. 4 were related to the primary dressing and 28 to the secondary dressing, of which 8 were attributed to maceration.

Group 2 (alginate dressing): 32 adverse events reported during the trial. 3 were related to the primary dressing and 29 to the secondary dressing, of which 9 were attributed to maceration.

Harding 2001

Total number of dressing changes:

Group 1 (hydrocolloid dressing): 1093

Group 2 (alginate dressing): 1186

Mean wear time days (SD) [median (range)]:

Group 1 (hydrocolloid dressing):  3.632 days (1.878) [3 (1 to 13)]; n = 66

Group 2 (alginate dressing):  3.271 days (1.944) [3 (1 to 9)]; n = 65

The trial authors reported that the between‐group difference in means was P value < 0.001

Mean number of dressing changes per healed ulcer:

Group 1 (hydrocolloid dressing):  7.4

Group 2 (alginate dressing):  12.1

P value for between‐group difference not reported

Mean cost to achieve ulcer healing (based on patients healed):

Group 1 (hydrocolloid dressing):  GBP 1184.09 (USD 1699.71)

Group 2 (alginate dressing):  GBP 1200.73 (USD 1723.59)

Mean cost per 1cm² reduction in ulcer size (all patients randomised):

Group 1 (hydrocolloid dressing):  GBP 59.22 (USD 85.01)

Group 2 (alginate dressing):  GBP 92.27 (USD 132.46)

Mean cost per 10% reduction in ulcer area:

Group 1 (hydrocolloid dressing):  GBP 80.15 (USD 115.06)

Group 2 (alginate dressing):  GBP 104.92 (USD 150.62)

Percentage of dressing changes associated with no pain:

Group 1 (hydrocolloid dressing): 82%

Group 2 (alginate dressing): 62%

The trial authors reported that the between‐group difference was statistically significant ( P value < 0.001). Numbers of dressings not reported 

Dressing performance – percentage recording “excellent” for overall ability to contain exudate:

Group 1 (hydrocolloid dressing): 44%

Group 2 (alginate dressing): 20%

Unclear whether denominator was the number of participants or the number of dressing changes.

Reported P value for between‐group difference = 0.002 

Dressing performance – percentage recording “excellent” for overall ease of dressing removal:

Group 1 (hydrocolloid dressing): 51%

Group 2 (alginate dressing): 24%

Unclear whether denominator was the number of participants or the number of dressing changes.

Reported P value for between‐group difference = 0.006

 Percentage of dressing changes with some adhesion to the wound bed:

Group 1 (hydrocolloid dressing): 38%

Group 2 (alginate dressing): 74%

The trial authors reported that the between‐group difference was statistically significant (P value < 0.001)

Number of dressing changes not reported

Review authors' comments: there were some minor discrepancies between numbers in main text and tables for cost information (data from main text were recorded here); discrepancies between primary and secondary references for outcomes of ease of removal and exudate handling (data from primary reference recorded here); unclear whether reported outcomes relating to pain at dressing change, exudate handling, ease of dressing removal and adhesion were rated by participants or investigators (or both).

Límová 2003

Total number of dressing changes over the course of the trial:

Group 1 (alginate dressing, Tegagen ™ HG): 69 (65 scheduled and 4 unscheduled)

Group 2 (alginate dressing, Sorbsan®): 61 (60 scheduled and 1 unscheduled) 

Mean (SD) comfort score during wear over number of visits:

Group 1 (alginate dressing, Tegagen ™ HG): 1.2 (SD 0.35) over 55 visits; n = 10

Group 2 (alginate dressing, Sorbsan®): 2.1 (SD 0.50) over 51 visits; n = 9

The trial authors reported a P value of 0.0005 for the between‐group difference 

Mean (SD) comfort score during dressing removal over number of visits:

Group 1 (alginate dressing, Tegagen ™ HG): 1.2 (SD 0.22) over 55 visits; n = 10

Group 2 (alginate dressing, Sorbsan®): 1.9 (SD 0.19) over 51 visits; n = 9

The trial authors reported a P value of 0.003 for the between‐group difference 

Percentage of visits where necrotic tissue was observed:

Group 1 (alginate dressing, Tegagen ™ HG): 59.7% of 55 visits; n = 10

Group 2 (alginate dressing, Sorbsan®): 68.9% of 51 visits; n = 9

The trial authors reported a P value of 0.57 for the between‐group difference 

Percentage of visits where debridement was required:

Group 1 (alginate dressing, Tegagen ™ HG): 18.7% of 55 visits; n = 10

Group 2 (alginate dressing, Sorbsan®): 40.7% of 51 visits; n = 9

The trial authors reported a P value of 0.18 for the between‐group difference 

Mean improvement in amount of necrotic tissue (lower score is better):

Group 1 (alginate dressing, Tegagen ™ HG): 2.5 over 55 visits; n = 10

Group 2 (alginate dressing, Sorbsan®): 1.5 over 51 visits; n = 9

The trial authors reported a P value of 0.38 for the between‐group difference 

Mean (SD) exudate absorption score over number of visits (lower score better):

Group 1 (alginate dressing, Tegagen ™ HG): 1.3 (SD 0.45) over 55 visits; n = 10

Group 2 (alginate dressing, Sorbsan®): 2.1 (SD 0.48) over 51 visits; n = 9

The trial authors reported a P value of 0.002 for the between‐group difference 

Percentage of clinic visits with medium or large amount of exudate observed:

Group 1 (alginate dressing, Tegagen ™ HG):  71.7% of 55 visits; n = 10

Group 2 (alginate dressing, Sorbsan®):  86.3% of 51 visits; n = 9

The trial authors reported a P value of 0.25 for the between‐group difference 

Mean (SD) ease of removal score over number of visits (lower is better):

Group 1 (alginate dressing, Tegagen ™ HG): 1.1 (SD 0.16) over 55 visits; n = 10

Group 2 (alginate dressing, Sorbsan®): 2.0 (SD 0.56) over 51 visits; n = 9

The trial authors reported a P value of 0.002 for the between‐group difference 

Proportion of participants reporting dressing adherence to the wound bed:

Group 1 (alginate dressing, Tegagen ™ HG): 0%

Group 2 (alginate dressing, Sorbsan®): 27.8%

The trial authors reported that the average percentage of dressing changes with adherence to the wound bed was significantly less in Group 1 (P value < 0.05).

Percentage of clinic visits with observation of peri‐wound skin as macerated, denuded, requiring medication:

Group 1 (alginate dressing, Tegagen ™ HG): 36.0%, 9.0%, 31.3%

Group 2 (alginate dressing, Sorbsan®): 54.4%, 31.9%, 65.2%

Reported P values for between‐group difference: macerated skin P value 0.30; denuded skin P value 0.04, medication required P value 0.07

Moffatt 1992

None reported

Smith 1994

Proportion of participants “improved remarkably” in quality of life at week 6:

Group 1 (hydrocolloid dressing): 42.9%

Group 2 (alginate dressing): 40.0%

The trial authors did not report the number of participants completing the quality of life assessment. P value for between‐group difference not reported. There was a reporting discrepancy between “improved remarkably” and the pre‐defined categories for this outcome (deteriorated markedly, deteriorated somewhat, no change, improved somewhat or improved markedly)

Number of dressings used per week:

Group 1 (hydrocolloid dressing): 1‐3

Group 2 (alginate dressing): 1‐2

Wear time:

The trial authors reported that both dressings were equivalent in terms of wear time, but no data by group or P value for between‐group difference were reported.

Mean total approximate cost of materials:

Group 1 (hydrocolloid dressing): GBP 431.73

Group 2 (alginate dressing): GBP 364.08

P value for between‐group difference not reported 

Mean ulcer pain score over past 2 weeks at 6 weeks:

Group 1 (hydrocolloid dressing): 1.46

Group 2 (alginate dressing): 2.15

The trial authors reported that the between‐group difference was not statistically significant. P value not reported 

Change from baseline in mean ulcer pain score over past 2 weeks at 6 weeks:

Group 1 (hydrocolloid dressing): ‐3.28

Group 2 (alginate dressing): ‐2.71

Estimated by review authors 

Mean pain score at dressing change at week 6:

Group 1 (hydrocolloid dressing):  1.73

Group 2 (alginate dressing): 2.16

P value for between‐group difference not reported 

Change from baseline in mean pain score at dressing change at 6 weeks:

Not reported and reviewer unable to estimate as data at week 6 only reported (no baseline) 

Proportion of participants reporting no sleep disturbance due to pain at week 2 and week 6:

Group 1 (hydrocolloid dressing):  31.25%, 78.6%

Group 2 (alginate dressing): 8.8%, 40.0%

The trial authors did not report whether the proportions were for all participants enrolled or only those completing the trial. Reported P value for between‐group difference = 0.0721, but unclear to which time point this refers or if it is for the test across time points 

Dressing performance (exudate handling):

The trial authors reported that the Group 2 dressing was “slightly superior” in terms of ability to contain exudate. However,  no data by group or P value for between‐group difference were reported 

Proportion of participants reporting ‘excellent’ for ease of dressing removal:

Group 1 (hydrocolloid dressing): 56.3%

Group 2 (alginate dressing): 8.3%

The trial authors did not report raw numbers and the denominator was not clear. Reported P value for between‐group difference was < 0.001. The trial authors reported that the Group 2 dressing often needed to be soaked off the ulcer. 

Number participants experiencing adverse events:

Group 1 (hydrocolloid dressing): 5/22 (23%) (withdrawals: pain, 1; ulcer infection, 1; possible allergy, 1; not thought to warrant withdrawal ‐ wound infection, 1; pain and erythema at the final visit, 1)

Group 2 (alginate dressing): 6/18 (33%) (withdrawals: pain, 4; ulcer infection, 2)