Raad 1998.

Methods	Multicentre RCT (USA)
Participants	The only information provided by the authors of this paper on the participants was that they were ".... critically ill patients ..."
Interventions	MR‐impregnated CVCs versus non‐impregnated CVCs
Outcomes	Catheter colonization, premature catheter removal, duration of systemic antibiotics use and durability of the antimicrobial activity
Notes	Sources of funding: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random sequence generation and allocation were described in detail, as follows: Quote: "Coated and uncoated catheters were packaged in identical trays, assigned a random number, and shipped to our study sites ... The randomization scheme consisted of blocks of six identical catheter trays: three for coated central venous catheters and three for control central venous catheters. Every block of six catheter trays was packed in a box. Central venous catheters were allotted to each eligible patient sequentially from the catheter trays which were removed from the box, one at a time, from top to bottom."
Allocation concealment (selection bias)	Low risk	Random sequence generation and allocation were described in detail, as follows: Quote: "Coated and uncoated catheters were packaged in identical trays, assigned a random number, and shipped to our study sites … The randomization scheme consisted of blocks of six identical catheter trays: three for coated central venous catheters and three for control central venous catheters. Every block of six catheter trays was packed in a box. Central venous catheters were allotted to each eligible patient sequentially from the catheter trays which were removed from the box, one at a time, from top to bottom."
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	The catheters were prepared in‐house from identical materials but the authors did not mention whether the final appearance of the prepared and unprepared catheters remained identical in appearance, and whether those involved in the study knew the difference
Blinding of outcome assessment (detection bias) Microbiological outcomes like catheter colonization	Unclear risk	The authors did not mention whether the assessors of the microbiological outcomes were blinded
Blinding of outcome assessment (detection bias) Clinical outcomes like CRBSI	Unclear risk	The catheters were prepared in‐house from identical materials but the authors did not mention whether the final appearance of the prepared and unprepared catheters remained identical in appearance, and whether those involved in the study knew the difference
Incomplete outcome data (attrition bias) All outcomes	Low risk	It appeared that all 40 participants initially randomized were analyzed
Selective reporting (reporting bias)	High risk	The outcomes of catheter colonization and premature catheter removal were reported in sufficient detail in the Results. However the usage of systemic antibiotics was reported in the form of median and range and not mean and standard deviation, and so the data were unsuitable to be included in our meta‐analysis
Other bias	Low risk	None identified