Citrate versus heparin lock for hemodialysis catheters: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Citrate solution has been suggested as an effective and safe catheter lock in hemodialysis. However, whether a citrate lock is superior to a heparin lock in preventing catheter-related infections and maintaining catheter patency is inconclusive. STUDY
DESIGN: A systematic review and meta-analysis was performed by searching in PubMed, EMBASE, Ovid, the Cochrane Library, and Web of Science databases and major nephrology journals. SETTING & POPULATION: Patients receiving hemodialysis with central venous catheters. SELECTION CRITERIA FOR STUDIES: Randomized controlled trials comparing citrate locks with heparin locks in hemodialysis patients with central venous catheters. INTERVENTION: Locking central venous catheters with citrate locks. OUTCOMES: Primary outcomes include catheter-related bloodstream infection (CRBSI), exit-site infection, catheter removal for poor flow, and thrombolytic treatment.
RESULTS: 13 randomized controlled trials (1,770 patients, 221,064 catheter-days) met the inclusion criteria. Pooled analyses found that citrate locks could significantly reduce the incidence of CRBSI (risk ratio [RR], 0.39; 95% CI, 0.27-0.56; P < 0.001). Subgroup analysis showed that antimicrobial-containing citrate locks (citrate + gentamicin, citrate + taurolidine, and citrate + methylene blue + methylparaben + propylparaben) were superior to heparin locks in the prevention of CRBSI (P < 0.001, P = 0.003, and P = 0.008, respectively), whereas citrate alone failed to show a similar advantage (P = 0.2). Low- (1.04%-4%) to moderate-concentration (4.6%-7%) citrate locks were associated with decreased CRBSI incidence (P < 0.001 and P = 0.003, respectively), but patients receiving high-concentration (30%-46.7%) citrate and heparin locks had similar incidences (P = 0.3). The incidence of bleeding episodes (RR, 0.48; 95% CI, 0.30-0.76; P = 0.002) was significantly lower in patients receiving citrate locks, whereas both groups were similar in terms of exit-site infection (P = 0.2), catheter removal for poor flow (P = 0.9), thrombolytic treatment (P = 0.8), all-cause death (P = 0.3), catheter thrombosis (P = 0.9), mean catheter duration (P = 0.2), CRBSI-free catheter survival (P = 0.2), and catheter-related readmission (P = 0.5). LIMITATIONS: All studies used in the meta-analysis were performed in Western countries. The applicability of our findings to other regions remains to be clarified.
CONCLUSIONS: An antimicrobial-containing citrate lock is better than a heparin lock in the prevention of catheter-related infection, while citrate alone fails to show a similar advantage. Citrate locks of low to moderate concentrations, rather than high concentration, were superior to heparin locks in preventing CRBSI. Citrate locks also might decrease bleeding episodes. No difference has been identified in the efficacy to prevent exit-site infection or preserve catheter patency between citrate and heparin locks.