Raad 1997.

Methods	Multicentre RCT (USA)
Participants	Quote: "Hospitalized patients 18 years of age or older who required a triple‐lumen polyurethane central venous catheter at a new insertion site were asked to participate. We excluded pregnant women, patients who were allergic to rifampin or tetracycline, patients with dermatitis or a burn over the insertion site, and patients for whom the anticipated duration of catheterization was less than 3 days.”
Interventions	MR‐impregnated CVCs versus non‐impregnated CVCs
Outcomes	Catheter colonization and CRBSI
Notes	Sources of funding: partly from the industry (catheter manufacturer or distributor) and partly from institutional research fund
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: ”All catheters were gas sterilized and placed in identical trays, and each tray was assigned an identification number. The trays were then randomly assigned into blocks of six: three with coated catheters and three with control catheters. Each block of trays was placed in boxes by Cook Critical Care, and the boxes were shipped to the five hospitals. When a patient was determined to be eligible, a tray was removed from the box (trays were removed one at a time, in sequential order from top to bottom), and that catheter was used for the patient. The catheter identification number was recorded on a data entry form and on the patient's medical chart.”
Allocation concealment (selection bias)	Low risk	Random sequence generation and allocation were described in detail, as follows: Quote: ”All catheters were gas sterilized and placed in identical trays, and each tray was assigned an identification number. The trays were then randomly assigned into blocks of six: three with coated catheters and three with control catheters. Each block of trays was placed in boxes by Cook Critical Care, and the boxes were shipped to the five hospitals. When a patient was determined to be eligible, a tray was removed from the box (trays were removed one at a time, in sequential order from top to bottom), and that catheter was used for the patient. The catheter identification number was recorded on a data entry form and on the patient's medical chart.”
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Neither the patient nor the clinician who inserted the device knew which catheter (coated or uncoated) had been used."
Blinding of outcome assessment (detection bias) Microbiological outcomes like catheter colonization	Unclear risk	There was no specific statement on whether the assessors of the microbiological outcomes were blinded to the status of the catheter sample
Blinding of outcome assessment (detection bias) Clinical outcomes like CRBSI	Low risk	Quote: "Neither the patient nor the clinician who inserted the device knew which catheter (coated or uncoated) had been used."
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	32/298 catheters (10.4%) were excluded from the analysis due to a failure to obtain cultures (17 from the study group and 15 from the control group). Although the number excluded appeared balanced between the 2 groups, in view of the relatively low event rates for CRBSI and catheter colonization, it was unclear whether the results would be altered substantially should data from the excluded samples be available
Selective reporting (reporting bias)	Unclear risk	The major clinical outcomes of CRBSI and catheter colonization were reported in sufficient detail in the Results. The authors provided a cost estimate of the 2 types of catheters, but the figures were presented narratively and were not suitable to be included in our meta‐analysis
Other bias	Low risk	None identified