Jameson 2010.

Methods	Study design: ITS
Participants	Surgeons Clinical speciality: orthopaedic surgery Level of training: fully trained Setting/country: hospital/inpatient/UK
Interventions	The PEM consisted of a guideline on prophylaxis against venous thromboembolism produced by NICE in April 2007. The recommendations were that all orthopaedic inpatients be offered an LMWH for the duration of their stay in hospital, while high‐risk patients including all patients aged over 60 years should continue treatment for 4 weeks after discharge
Outcomes	1 process outcome: use of LMWH following a lower limb arthroplasty 2 patient outcomes: complications from hip or knee replacement surgeries (venous thromboembolic events) complications from hip or knee replacement surgeries (thrombocytopenia)
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Intervention independent of other changes ‐ ITS	Unclear risk	No information was provided
Shape of Intervention effect pre‐specified ‐ ITS	Unclear risk	Quote, pg. 124: "the early effect of the NICE guidelines has yet to be reported. This paper aims to examine their impact on the use of LMWH in patients  undergoing arthroplasty of the lower limb in England and Wales, and to analyze the effect on the national rates of complications relating to venous thromboembolic prophylaxis"
Intervention unlikely to affect data collection ‐ ITS	Low risk	The intervention (NICE guidelines on prophylaxis against venous thromboembolism)  did not affect either the source or method of data collection
Blinding of outcome assessors (detection bias) ‐ ITS All outcomes	Low risk	The outcome was objective
Incomplete outcome data (attrition bias) ‐ ITS All outcomes	Low risk	COMMENT: an exclusion criterion was described as "missing date of operation" in patient records and while the number and distribution between pre‐ and post‐guideline periods is not given, it is likely to be small and evenly distributed
Selective reporting (reporting bias) ‐ ITS	Low risk	All relevant outcomes in the methods section were reported in results section
Other bias ‐ ITS	Low risk	There was no evidence of other risks of bias