This review concluded that antimicrobial lock solutions containing antibiotics significantly reduced catheter-related bloodstream infections in patients undergoing haemodialysis and should be considered for use in routine practice. This was a generally well-conducted review and the authors' conclusions appeared reliable.

To determine the effectiveness of antimicrobial catheter lock solutions for the prevention of catheter-related infections in patients undergoing haemodialysis.

The authors searched the Cochrane Register of Controlled Trials and PubMed to November 2007 without language restrictions. Search terms were reported. Unpublished studies were sought in reference lists of selected studies, conference proceedings, trial registries, databases of ongoing trials, new drug application documents and by contacting the investigators of included trials.

Randomised controlled trials (RCTs) that compared any single or combination antimicrobial (antibiotic, citrate, taurolidine or alcohol) catheter lock solution with heparin or another antimicrobial catheter lock solution in adults or children with end-stage renal disease undergoing haemodialysis through central catheters were eligible for the review. Studies could include up to 30 per cent of patients with acute renal failure. All antimicrobial solutions could be given with heparin or EDTA. The primary outcomes were clinically significant bloodstream infection from any cause, catheter-related bloodstream infections and need for removal of the catheter. A large number of secondary outcomes were listed. The majority of the included trials assessed antibiotic catheter lock solutions and all used heparin as the comparator. Mean age of patients in included trials ranged from 47 to 77 years. The percentage of tunneled catheters ranged from 100 per cent (in the majority of included trials) to 0.

Two reviewers independently selected studies for the review.

Validity was assessed based on adequacy of randomisation, allocation concealment and blinding. The authors did not state explicitly how the validity assessment was performed.

Data on numbers of participants and events in each group were used to calculate relative risks (RRs) and associated 95% confidence intervals (CIs) per patient and per catheter-day. Data were extracted by intention-to-treat if possible. Study authors were contacted for missing data. Two reviewers independently extracted data for the review.

Studies were pooled by meta-analysis using a Mantel-Haenszel fixed-effect model. Trials of antibiotic and non-antibiotic catheter lock solutions were analysed separately. Heterogeneity was assessed using the Χ² test and the I² measure of inconsistency. Substantial heterogeneity (I²>50%) was investigated by subgroup analysis and meta-regression. Publication bias was assessed using funnel plots and the small studies effect was assessed using Egger's test of the intercept.

Sixteen RCTs were included in the review: 11 (n = 924; 176,332 catheter days) assessed antibiotics; and five (n = 661; 63,345 catheter-days) assessed other antimicrobials. Follow-up ranged from six to 16 months. Seven trials had adequate allocation concealment and allocation sequence generation. Six were double-blind. None of the trials assessed all-cause bloodstream infection. Antibiotic lock solutions significantly reduced catheter-related bloodstream infections compared with heparin (RR per patient 0.44, 95% CI: 0.38, 0.50; RR per catheter-day 0.37, 95% CI: 0.30, 0.47; 11 RCTs). Heterogeneity was significant in both analyses. Subgroup analyses of larger trials with adequate randomisation revealed smaller, but still significantly significant reductions in infections without significant heterogeneity (RR 0.60, 95% CI: 0.54, 0.67; eight RCTs). Catheter removal rates were also significantly reduced by antibiotic lock solutions compared with heparin (RR per patient 0.35, 95% CI: 0.23, 0.55; RR per catheter-day 0.34, 95% CI: 0.21, 0.55; five RCTs) without significant heterogeneity. Non-antibiotic lock solutions also significantly reduced catheter-related infections and catheter removal, again with significant heterogeneity for catheter-related infections. Analysis of funnel plots revealed a significant small-studies effect. Results for other analyses and outcomes were reported.

Antibiotic catheter lock solutions reduce catheter-related bloodstream infections and catheter removal rates in patients undergoing haemodialysis.

This review had clear inclusion criteria for participants, interventions, outcomes and study designs. The main search was limited to two databases, but no language restrictions were imposed and a range of other sources were searched for published and unpublished studies. Publication bias was assessed and a significant small-study effect was found; this reflected a lack of small studies with non-significant results and could be an indication of publication or other bias. Validity was assessed and the results were used in the synthesis. Study selection and data extraction were performed in duplicate, minimising the risk of bias and errors, although it is uncertain whether similar methods were used for validity assessment. Relevant details of included studies were presented. Studies were pooled by meta-analysis. Antibiotic and non-antibiotic solutions were analysed separately. Heterogeneity was assessed and possible sources explored thoroughly. This was a generally well-conducted review. The authors' conclusions followed from the evidence presented and were likely to be reliable. The effect estimate derived from the larger and better-quality trials may be more robust than that from all the trials.

Practice: The authors stated that use of antibiotic catheter lock solutions in conjunction with other prevention methods should be considered in routine clinical practice.

Research: The authors stated that further studies were needed to assess the efficacy of citrate and citrate-taurolidine compared with heparin and antibiotics, and that the development of resistance to antibiotic catheter lock solutions should be assessed in long-term prospective studies.

Not stated.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.