Table 2.

Bias and blinding.

Paper	Randomization technique	Participants blinded	Investigators blinded	Outcome reporting	Attrition bias
Coutinho et al. (2010)	Non-randomized	No blinding	No blinding	Both primary and secondary outcomes were reported fully.	11 patients were lost to follow up in the LMWH group. 25 patients were lost to follow up in UH group. 9% and 8% respectively.
Misra et al. (2012)	Computer generated number allocation was used to randomize the patients	Participants were not blinded	Investigators were not blinded	Both primary and secondary outcomes were reported fully.	1 patient lost to follow up in UH group
Afshari et al. (2015)	Computer generated number allocation was used to randomize patients.	Pre-printed medication codes were used to blind patients.	Investigators were blinded using pre-printed medication codes (However it is not stated whether blinding between IV and SC routes occurred). Treatment and evaluation was undertaken by different personnel.	Both primary and secondary outcomes were reported fully.	8 patients were lost to follow up