Weed 2004.
| Methods | Design: Randomised double‐blind placebo controlled trial Number of participant centres: 1 Setting: Dermatology department Country: USA Unit of randomisation: the patient Unit of analysis: the patient Follow‐up: 24 weeks |
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| Participants | Number randomised (patients): 26 (15 experimental group and 11 control group) Number of ulcers assessed: 1 per patient Wound aetiology: Mixed 9; multifactorial 7; neurotrophic 5; venous ulcers 3; traumatic 1; idiopathic and 1 pressure ulcer Age (mean and SD): 67.6 (11.9) years (experimental group) and 57.8 (18.2) years (placebo group) Sex: 11 F/15 M Inclusion criteria: Adults of both sexes with a chronic skin leg ulcer and an evolution of at least 8 weeks. Arterial, venous, neuropathic or vascular (small‐vessel) ulcers. Hb > 9.0g/dL and a platelet count > 100 x 109/L Exclusion criteria: Angina pectoris; symptomatic hypotension; myocardial infarction; class III or IV congestive heart failure; clotting function disorders; or a platelet count < 100 x 109/L; osteomyelitis; wounds caused by burns or irradiation; wounds > 100 cm2; and pregnancy or lactation |
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| Interventions | Experimental group: Autologous platelet lysate combined with collagen Control group: Platelet‐poor plasma combined with collagen (placebo group) for the first 12 weeks of therapy. After 12 weeks, there was a washout period of two weeks. During this washout period, patients applied only normal saline‐moistened gauze twice‐daily to their ulcerations. Patients whose ulcers had not healed were then assigned to receive whichever treatment they had not received in the previous 12 weeks. Patients were instructed to apply the product in a thin layer over the entire surface of the wound. Xeroform gauze was applied in a double layer over the platelet product, and a sterile gauze dressing was placed over this. The entire wound site was covered with a gauze wrap Length of treatment: Twice a day for 12 weeks |
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| Outcomes | Complete healing (100% epithelialisation). Rate of wound healing (ulcer surface depending on the duration of the treatment) | |
| Notes | Funding was not specified. Originally, this study was designed to include a higher number of patients: "This study was originally designed to accrue 40 patients in each group; the actual number of patients enrolled in the study was small and the study was not powered to detect significance. The study had to be terminated prematurely because of the difficulty of enrolling patients." At baseline, the experimental group was older than the control group | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "The patients were randomly assigned to receive either platelet lysate product mixed with collagen (the treatment group) or platelet‐poor plasma mixed with collagen (the placebo group) for the first 12 weeks of therapy" Comments: How the allocation sequence was generated is not specified |
| Allocation concealment (selection bias) | Unclear risk | Not specified |
| Blinding of participants (performance bias and detection bias) | Low risk | Quote: "Plasma and platelet lysate products were indistinguishable in physical appearance (straw‐coloured material)." "The placebo product was composed of platelet‐poor plasma added to collagen. This placebo product looked, smelled, and behaved like the autologous platelet lysate product. Both products were packaged and prepared identically (i.e. freezing technique)" Comments: It was judged that the participants were likely blinded to the intervention because both products were similar |
| Blinding of personnel (performance and detection bias) | Low risk | Quote: "Plasma and platelet lysate products were indistinguishable in physical appearance (straw‐coloured material)." "The placebo product was composed of platelet‐poor plasma added to collagen. This placebo product looked, smelled, and behaved like the autologous platelet lysate product. Both products were packaged and prepared identically (i.e. freezing technique)" Comments: It was judged that the personnel were likely blinded to the intervention because both products were similar |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Quote: "Plasma and platelet lysate products were indistinguishable in physical appearance (straw‐coloured material)." "The placebo product was composed of platelet‐poor plasma added to collagen. This placebo product looked, smelled, and behaved like the autologous platelet lysate product. Both products were packaged and prepared identically (i.e. freezing technique)" Comments: It was judged that the outcome assessors were likely blinded to the intervention because both products were similar |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | There were no exclusions after randomisation |
| Selective reporting (reporting bias) | Low risk | The results of all outcomes were presented. The trial protocol was not sought |
F: female M: male Hb: haemoglobin IV: intravenous PDWHF: platelet‐derived wound healing formula PRGF: plasma‐rich growth factor PRP: platelet‐rich plasma SD: standard deviation