Interventions:
The selection of the two comparators was appropriate. The authors stated that the trial was pragmatic and the management of leg ulcers was carried out in accordance with the normal practice. The choice of the compression bandage was based on local practice. All silver-donating dressings available in the authors’ setting were reported. The typical non-silver dressing was any non-antimicrobial low-adherence dressing from any manufacturer.
Effectiveness/benefits:
The use of a RCT should have ensured the validity of the clinical analysis due its randomisation procedure, which should have minimised the impact of selection bias and confounding factors. The sample size was justified on the grounds of power calculations, the details of which were clearly reported, but the study was only powered to detect statistically significant differences in the healing rate, which was the primary endpoint. Strengths of the analysis were the use of the intention-to-treat principle, the multi-centre design, and the baseline comparability of study groups with respect to most of the clinical and demographic characteristics. In general, the clinical analysis was well conducted and reported. The authors noted some potential limitations, such as the differences found in the clinical results between the two areas where the study took place. The derivation of utility values used to calculate the QALYs was clearly presented. Two approaches were used and neither of them demonstrated a statistically significant superior profile for silver dressings. The assessment of the potential factors affecting quality of life was investigated in a regression analysis, the key details of which were reported. The authors highlighted the difficulties of measuring quality of life in patients with leg ulcers and pointed out the need for a specific measure of quality of life for this patient population, who often suffer from co-morbidities.
Costs:
Extensive details of the economic analysis were presented in a separate report. In general, the cost categories were consistent with the economic viewpoint, but the unit costs and their sources were not reported. The data on the patient sample used to derive the information on patterns of resource consumption were provided, and the methods used to deal with missing values were reported. Standard statistical tests were used to detect differences in the costs between the two groups. The price year was reported, which will allow reflation exercises to be carried out in other time periods.
Analysis and results:
The incremental approach used to synthesise the costs and benefits was appropriate. The results were clearly presented and discussed. The issue of uncertainty was appropriately investigated using a valid approach. The authors stated that a detailed description of the methods and of the cost-effectiveness modelling was presented in a separate report, which should also contain more details on the cost data.
Concluding remarks:
The methodology appears to have been valid, which enhances the validity of the authors’ conclusions.
