Five studies in relation to surgical wounds healing by secondary intention, 28 trials evaluating 31 comparisons of treatments in relation to pressure sores, and 60 studies in relation to leg ulcers were included.
Treatments for surgical wounds healing by secondary intention: one study found a statistically-significant reduction in healing time with traditional wet-to-dry dressings, compared with topical applications of aloe vera, for all wound types (OR -30, 95% CI: -55.01, -4.99) and for vertical incisions (OR -37, 95% CI: -67.26, -6.74).
Treatments for pressure sores: a single report suggested that the topical application of insulin was of significant benefit for wound healing when compared with standard nursing care (p=0.05). A meta-analysis of 5 reports (chi-squared=5.76, d.f.=4, p=0.218) comparing a hydrocolloid dressing with a traditional treatment suggested that treatment with hydrocolloid resulted in a statistically-significant improvement in the rate of pressure sore healing (OR 2.57, 95% CI: 1.58, 4.18).
Treatments for leg ulcers: compared with a control preparation, both mononuclear cultured cells in culture medium and topical ketanserin significantly increased healing rates in one trial of arterial leg ulcers. Collagen sponges appeared to be effective in 2 trials of leg ulcers but there were insufficient data to determine the significance of these results.
Nine trials compared hydrocolloid dressings with traditional or control dressings for venous ulcers. The meta-analysis of the 8 studies (chi-squared=16.72, d.f.=7, p=0.019) providing data on the proportion of ulcers completely healed during the trial period, demonstrated no significant difference in this outcome (pooled OR 1.45, 95% CI: 0.83, 2.34). Two trials compared semi-permeable film dressings with traditional or control therapies: one found a larger reduction in wound area under the film dressing (ES 32.15, 95% CI: 10.18, 54.12) but the other found no significant difference in healing rates (OR 1.48, 95% CI: 0.5, 4.3). Two trials compared foam dressings with traditional or control therapies: one trial found a reduction in wound area with foam dressing (ES 144, 95% CI: 48.8, 239) but the other found no difference in the proportion of ulcers healed (OR 1.67, 95% CI: 0.8, 3.3). Woven zinc oxide paste bandage was more effective than either an alginate dressing (OR 3.6, 95% CI: 1.1, 6.14) or a zinc oxide-impregnated stockinette (OR 1.83, 95% CI: 0.78, 4.28) in one trial.
In 2 trials comparing different hydrocolloids, no significant difference in healing rates was found. Two trials comparing hydrocolloids with foam dressings found no statistically-significant difference in the proportion of ulcers healed over the trial period. Pooling the data from the two trials (chi-squared=0.00, d.f.=1, p=1) again showed no difference in healing rates (OR 1.0, 95% CI: 0.48, 2.07).
In trials of topical agents, one trial reported a higher proportion of ulcers that healed with allopurinol (OR 2.98, 95% CI: 1.28, 6.94) and with dimethyl sulfoxide (OR 3.28, 95% CI: 1.39, 7.71) than when compared with placebo. Of 2 trials comparing hyaluronic acid with control, one found a difference in daily healing rate that favoured the hyaluronic acid (ES 34), and the other found no difference in the proportion of ulcers healed over the trial period (OR 0.72, 95% CI: 0.2, 2.56).
Four trials compared biological dressings with traditional therapies. None found statistically-significant differences in results.
Two trials compared dressings with topical preparations. There was no difference in the proportion of ulcers healed between patients treated with cryopreserved cultured allografts or a hydrocolloid (OR 0.83, 95% CI: 0.21, 3.2), though the former-treated ulcers had a higher rate of epithelialisation. A collagen dressing healed a higher proportion of ulcers than treatment with daily antiseptic (OR 26.6, 95% CI: 2.3, 308).
A comparison of buffered acidifying ointment and ointment reported there was no difference in the proportion of ulcers healed, but there was a higher rate of epithelialisation with the buffered ointment group. In another trial there were higher healing rates with amino acid soaks than with saline soaks.
Quality assessment (treatments for surgical wounds healing by secondary intention and treatments for pressure sores): the majority of trials had methodological weaknesses. Fewer than 6% of studies reported an a priori estimate of the number of participants required to have sufficient power to detect a clinical effect as statistically significant, the median number of wounds recruited to a trial was 50 (range: 14 - 168). Blinding of investigators at outcome assessment was reported in fewer than 18% of trials. One or more patient characteristics were recorded by treatment group in 80% of studies, but wound size at baseline was reported in only 60%. Withdrawals occurred in most trials and were recorded by group and cause in 88% of trials where it was appropriate, but only 13% analysed the results on an ITT basis. Seventy-six per cent of trials described inclusion criteria, but information that indicated whether participants had been truly randomised to alternative treatments was given in only 20%.
Quality assessment (treatments for leg ulcers): the majority of trials had methodological weaknesses. Fewer than 9% of studies reported an a priori estimate of the number of participants required for the trial to have sufficient power to detect a clinical difference as statistically significant. The median number of wounds recruited to a trial was 48.5 (range: 9 - 233). Blinding of investigators at outcome assessment was reported in fewer than 7% of trials. One or more patient characteristics were recorded by treatment group in 36 out of 48 (75%) studies, but wound size at baseline (by group) was reported in only 30 of the 48 (62%) studies. Withdrawals occurred in most trials; the number and cause were recorded by group in 46% of trials where it was appropriate, but only 18% performed an ITT analysis. Sixty-two per cent described relevant inclusion criteria, but information that indicated that participants had been randomised with allocation concealment was given in only 10% of trials.
Publication bias assessment: the overall funnel plot of all studies comparing a traditional treatment with a modern therapy showed little evidence of asymmetry. However, for the subgroup of trials that compared a hydrocolloid dressing with a traditional treatment, asymmetry was clearly evident. Publication bias for studies favouring hydrocolloid treatment may be responsible for this result. Further analyses are reported in the paper.