| Methods |
Single‐centre RCT (UK) |
| Participants |
Participants over 18 years of age who were admitted for routine surgical procedures including coronary bypass grafting who required a CVC, with no known allergy to benzalkonium chloride |
| Interventions |
Benzalkonium‐coated CVCs versus uncoated CVCs |
| Outcomes |
Catheter colonization at subcutaneous and distal catheter segments, clinically diagnosed sepsis, catheter‐related local infection and in‐vitro antibacterial activity |
| Notes |
Sources of funding: industry (catheter manufacturer or distributor) |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Quote: participant recruitment: "Following informed consent each patient was randomly assigned to either the benzalkonium chloride catheter group or the control group." The method of random sequence generation was not stated |
| Allocation concealment (selection bias) |
Unclear risk |
Quote “The randomization system consisted of sequentially sealed envelopes each of which contained information stating the specified study catheter the patient should receive.” It was not stated whether the envelopes were opaque |
| Blinding of participants and personnel (performance bias)
All outcomes |
Unclear risk |
There was no clear statement about blinding. The study and control catheters were produced by the same manufacturer, but it was unclear whether the 2 types of catheter were identical in their appearance, and whether any measures were taken to blind those involved in the study |
| Blinding of outcome assessment (detection bias)
Microbiological outcomes like catheter colonization |
Unclear risk |
It was not stated whether the assessors of the microbiological outcomes were blinded |
| Blinding of outcome assessment (detection bias)
Clinical outcomes like CRBSI |
Unclear risk |
There was no clear statement about blinding. The study and control catheters were produced by the same manufacturer, but it was unclear whether the 2 types of catheter were identical in their appearance, and whether any measures were taken to blind those involved in the study |
| Incomplete outcome data (attrition bias)
All outcomes |
Unclear risk |
31/235 catheters (13.2%) were excluded from the analysis (11 from the study group and 20 from the control group). The authors stated that the catheters were "not available for microbiological analysis", and gave no further reasons. The authors stated that the characteristics of the 2 study groups (after postrandomization exclusions) were similar. However, in view of the low event rates for the outcomes of clinically diagnosed sepsis and catheter‐related local infection, it was unclear whether data from the excluded catheters, had they be available, would have changed the results substantially |
| Selective reporting (reporting bias) |
Unclear risk |
All the clinically relevant outcomes specified in the Methods, including clinically diagnosed sepsis, catheter‐related local infection, catheter colonization and in‐vitro antimicrobial activity were reported in sufficient detail in the Results. However, the latter outcome was not included in our meta‐analysis as it was not a prespecified outcome for our review |
| Other bias |
Low risk |
None identified |
