Gentamicin Lock Therapy and Duration‐Dependent Catheter‐Related Bloodstream Infection Risk in Hemodialysis

ABSTRACT Introduction Clinical guidelines recommend antimicrobial lock solutions when infection rates exceed specific thresholds, yet their ability to modify duration‐dependent risk accumulation remains unexplored. This study compared catheter‐related bloodstream infection (CRBSI) outcomes and duration‐modifying effects between gentamicin‐heparin and heparin‐only lock protocols. Methods This retrospective dual‐center cohort study (January 2020–December 2024) included 266 maintenance hemodialysis patients with tunneled catheters (gentamicin‐heparin: n = 198, 52,193 catheter‐days; heparin‐only: n = 68, 15,443 catheter‐days). Primary outcome was CRBSI incidence density. Firth logistic regression with interaction analysis explored duration‐modifying effects. Safety was evaluated through antimicrobial resistance patterns and a cross‐sectional hearing assessment (15 gentamicin‐exposed patients vs. 15 matched controls) using the Hearing Handicap Inventory for the Elderly‐Screening Version (HHIE‐S). Findings Gentamicin‐heparin lock was associated with a 67% reduction in CRBSI (0.17 vs. 0.52 per 1000 catheter‐days; incidence rate ratio 0.33, 95% CI 0.13–0.86, p = 0.024). Stratified analysis revealed divergent duration‐risk relationships: each 30‐day increment significantly increased CRBSI risk with heparin‐only (OR 1.11, p = 0.006) but not with gentamicin‐heparin (OR 1.02, p = 0.547). The duration‐protocol interaction approached significance (coefficient −0.089, p = 0.061), suggesting gentamicin lock may attenuate time‐dependent risk accumulation. Among CRBSI isolates in the gentamicin cohort, 87.5% (7/8) demonstrated gentamicin resistance. HHIE‐S scores did not differ significantly between the gentamicin and control groups ( p = 0.507). Discussion Gentamicin‐heparin lock effectively reduced CRBSI incidence. Stratified analysis suggested attenuation of duration‐dependent risk, though the interaction did not reach significance ( p = 0.061). Sustained clinical efficacy despite high resistance, alongside a favorable preliminary hearing safety profile, suggests its clinical utility while warranting careful stewardship and prospective study.