Humar 2000.

Methods	Multicentre RCT (Canada) Study period: Period of study not specified but authors stated that study conducted over 1 year (paragraph 1, results) Setting: hospital‐wide
Participants	'Patients and methods', 'Patients': "All patients > 18 years of age who had CVCs inserted for any purpose were eligible for inclusion in the study, provided the treating physician felt the inserted catheter would be present for a minimum of 72 hours." Number of participants: 242 Number of catheters; 374 Age: mean of 58.3 years +/‐ range of 16.8 years (chlorhexidine group ) and 62.2 years +/‐ range of 16.0 years (povidone‐iodine group) Sex: 78% male in chlorhexidine group and 72% male in povidone‐iodine group.
Interventions	Comparison of 2 active agents for initial and subsequent cutaneous antisepsis for catheter care. Intervention A: 10% povidone‐iodine. Intervention B: 0.5% tincture of chlorhexidine. Outcomes assessed at various points during in‐patient stay.
Outcomes	Catheter‐related BSI (definite and probable) Catheter colonisation Insertion site infection
Notes	Funding source: the study was funded by Physicians Services Incorporated (North York, Ontario, Canada) and Medi‐Flex (Overland Park, KS).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	'Methods', 'Study design': Randomisation was achieved "by the use of blinded block randomisation schedule".
Allocation concealment (selection bias)	Unclear risk	Although the authors stated that the block randomisation schedule was "blinded", there was no further information provided on how treatment assignment was allocated using the random sequence generated at the time of enrolment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	The authors did not report whether blinding was achieved; blinding for clinical outcome assessment was highly unlikely because the antiseptic solutions used differed in appearance.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding for microbiological outcome assessment was unclear as this was not stated in the paper.
Incomplete outcome data (attrition bias) All outcomes	High risk	For the outcomes of catheter‐related BSI and catheter colonisation, trialists only analysed 180 out of 242 patients that were initially enrolled (74%). The authors stated that 62 catheters were not analysed because the catheter tips were not available for culture, the underlying reasons of which were not provided. For the outcome of insertion site ("exit site") infection which was not dependent on catheter culture, trialists included all 242 patients in the analysis. The authors appeared to follow the intention‐to‐treat principle as they analysed the patients for whom the data was available in the originally assigned group.
Selective reporting (reporting bias)	Low risk	Authors reported all the outcomes stated in the 'Methods' with sufficient detail in the 'Results'.
Other bias	High risk	The study employed a block randomisation schedule with high likelihood that blinding of participants and personnel could not be achieved. This posed a risk to the integrity of the random sequence which would be vulnerable to disruption following educated guesses by those involved in the study on the likely assigned group of the future participants.