Both interventions were well described including their dosage. UFH appears to be a relevant comparator as it represented current practice in the authors’ setting.
The effectiveness data were derived from a cross-over trial. This design is one that is subject to a number of limitations and so the possibility of bias in the results cannot be ruled out. Further, power calculations do not appear to have been performed, which does not allow any objective judgement to be made about the adequacy of the sample size.
The authors did not report a study perspective, so it was not clear if the appropriate cost categories were included. No statistical analysis of the costs was performed. The price year was not reported, so the results cannot be re-valued in future years.
Analysis and results:
No synthesis of the effectiveness and cost data was carried out. In effect, a cost-consequence analysis was carried out. The study results were relatively well reported. For one of the outcome measures (bleeding times) data were missing for nine patients receiving LMWH, compared with no patients receiving UFH, but it was not clear how this impacted on the study results. The impact of uncertainty, on the study parameters, was not investigated which makes it difficult to assess how robust the results were. The authors highlighted the small number of patients as a limitation to their study.
There were a few limitations to the study's methodology, especially concerning the effectiveness estimates and the lack of sensitivity analysis. For these reasons the authors' conclusions should be considered with a degree of caution.