Abstract: Thirty-nine studies, enrolling 4216 participants, were included in this review, however only 30 studies, involving 3392 participants, contained enough data to be meta-analysed. Risk of bias was low or unclear for most domains in the majority of the included studies. Studies compared antimicrobial lock solutions (antibiotic and non-antibiotic) to standard sealing solutions (usually heparin) of the CVC for HD. Fifteen studies used antibiotic lock solutions, 21 used non-antibiotic antimicrobial lock solutions, and 4 used both (antibiotic and non-antibiotic) lock solutions. Studies reported the incidence of CRI, catheter thrombosis, or both. Antimicrobial lock solutions probably reduces CRI per 1000 catheter-days (27 studies: RR 0.38, 95% CI 0.27 to 0.53; I2 = 54%; low certainty evidence), however antimicrobial lock solutions probably makes little or no difference to the risk of thrombosis per 1000 catheter days (14 studies: RR 0.79, 95% CI 0.52 to 1.22; I2 = 83%; very low certainty evidence). Subgroup analysis of antibiotic and the combination of both lock solutions showed that both probably reduced CRI per 1000 catheter-days (13 studies: RR 0.30, 95% CI: 0.22 to 0.42; I2 = 47%) and risk of thrombosis per 1000 catheter-days (4 studies: RR 0.26, 95% CI: 0.14 to 0.49; I2 = 0%), respectively. Non-antibiotic antimicrobial lock solutions probably reduced CRI per 1000 catheter-days for tunnelled CVC (9 studies: RR 0.60, 95% CI 0.40 to 0.91) but probably made little or no difference with non-tunnelled CVC (4 studies: RR 0.93, 95% CI 0.48 to 1.81). Subgroup analyses showed that antibiotic (5 studies: RR 0.76, 95% CI 0.42 to 1.38), non-antibiotic (8 studies: RR 0.85, 95% CI 0.44 to 1.66), and the combination of both lock solutions (3 studies: RR 0.63, 95% CI 0.22 to 1.81) made little or no difference to thrombosis per 1000 catheter-days compared to control lock solutions. Antibiotic antimicrobial and combined (antibiotic-non antibiotic) lock solutions decreased the incidence of CRI compared to control lock solutions, whereas non-antibiotic lock solutions reduce CRI only for tunnelled CVC. The effect on thrombosis incidence is uncertain for all antimicrobial lock solutions. Our confidence in the evidence is low and very low; therefore, better-designed studies are needed to confirm the efficacy and safety of antimicrobial lock solutions.

Plain-language summary: We included 39 studies, including 3,945 participants undergoing HD through a CVC. The studies compared CVC sealing solutions with heparin to antimicrobial lock solutions. Fifteen studies used only antibiotic lock solutions, 21 used non-antibiotic lock solutions, and 4 used both (antibiotic and non-antibiotic) lock solutions. Studies measured the incidence of CRIs and catheter thrombosis, or both. Overall quality of the studies was low for CRIs and very low for thrombosis. There was no information on funding sources for most of the studies. In general antimicrobial lock solutions are likely superior to standard solutions in preventing CRIs among patients undergoing HD through a CVC, but non-antibiotic solutions did not prove to reduce CRI. They are no worse than heparin at preventing thrombosis. Other adverse effects were not reported in most studies. Our confidence in these results is low due to the quality of the studies. Some antimicrobial (antibiotic and the combination of antibiotic-non antibiotic) lock solutions decrease the incidence of CRIs compared to heparin. Their effect on CVC permeability remains unclear. The quality of the studies is low and very low, respectively; therefore, more studies are needed to confirm the benefits and harms of antimicrobial lock solutions.