CRD summary: This review examined the effects of heparin for the treatment of deep vein septic thrombosis. The authors tentatively concluded that the timely use of heparin with appropriate antibiotics may be beneficial. The overall reliability of this conclusion is uncertain, given the lack of controlled evidence and methodological weaknesses in the review process.

CRD commentary: The review question and inclusion criteria were clear and sufficient information was given about the indications for intervention, medication regimens and findings of the primary studies. The search was adequate, though potentially limited by language restrictions and the failure to seek unpublished studies. It was not clear whether appropriate procedures for the study selection, quality assessment and data extraction processes were undertaken, thus the potential for reviewer bias and error cannot be determined. There was minimal detail about the study design and no evidence of a systematic evaluation of the validity of the included studies; this makes it difficult to assess the reliability of the findings. The narrative synthesis of the results was appropriate, though the results of the sole RCT were not highlighted.

The authors' conclusions tentatively favour the use of heparin. However, given the uncertain quality of the included studies, the lack of controlled evidence and the inconclusive findings of the sole RCT, the overall reliability of their conclusions is uncertain. The authors appropriately highlight the need for controlled studies in this area.