Antibiotic catheter lock: An adjunct therapy for recurrent tunneled hemodialysis catheter infections

INTRODUCTION

End-stage kidney disease (ESKD) is a major public health concern for health systems across the globe.^[1,2] The rising incidence and prevalence of ESKD have significantly impacted service provision for many patients. The cost of maintenance hemodialysis (HD) is rising, and many countries face major obstacles in providing the necessary quality of care.^[2,3] An arteriovenous fistula (AVF) is the primary and preferred access method to provide the necessary HD to keep patients alive.^[4] However, a small number of patients may be unable to maintain such access for various reasons.^[5] Consequently, tunneled HD catheters (THDC) may serve as their only lifeline. Nevertheless, repeated infections pose a major challenge to this management strategy.

Infections are common problems facing clinicians who care for HD patients and represent the second leading cause of mortality, following cardiovascular diseases. They play a key role in patient outcomes, accounting for almost 1,300 hospitalizations per 1,000 patient-years.^[6] Researchers have reported that HD catheters increase the risk of hospitalization for infection and death by almost 200–300% compared to patients with an AVF or graft.^[7,8] Furthermore, catheter-related bloodstream infections (CRBSIs) alone have an increased incidence of up to more than five episodes per 1,000 catheter-days and are associated with increased morbidity, hospitalization, and mortality.^[9,10]

In addition, Saran et al., reported that the rate of hospitalization due to infections in HD patients rose by 34%, according to data from the US Renal Data Registry.^[11] Another study from the USA found that the cumulative risk of CRBSI exceeded 50% within 6 months among the HD population.^[12] Consequently, research has shown that the frequency of different types of organisms varies greatly among series, with Staphylococcus aureus accounting for 3–74%, Staphylococcus epidermidis for 7–42%, and Gram-negative rods for 5–45% of CRBSIs.^[13]

Therefore, the present study describes the clinical course of four patients undergoing HD through a THDC, which served as their final access option (as all were unfit for AVF/ AVG), who experienced recurrent CRBSIs.

CASE SERIES

Results

The Al Seeb Renal Dialysis Center serves over 200 HD outpatients in the Muscat region. Of these, 160 patients receive dialysis through an AVF or AVG, while 40 utilize a tunneled catheter. Among the catheter group, 26 are awaiting AVF/AVG creation, and 14 are permanently unfit for AVF/AVG. The four cases in this study represent patients from the latter group who experienced recurrent CRBSIs in 2022, as shown in Figure 1.

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Figure 1: The distribution of vascular access types in hemodialysis patients. AVF: Arteriovenous fistula, AVG: Arteriovenous fistula graft, CRBSI: Catheter-related bloodstream infections.

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Following the implementation of the antibiotic locks, notable improvements were observed in laboratory parameters, particularly in markers of inflammation and anemia management.

All patients demonstrated a marked decrease in their required erythropoietin (EPO) doses following the eradication of recurrent infections, leading to a substantial reduction in medication costs, as shown in Figure 2.

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Figure 2: The change in erythropoietin dose before and after antibiotic lock therapy.

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Financial data obtained from the Royal Hospital indicated that the average healthcare cost per episode of HD-CRBSI was approximately $6,000 USD per admission. This cost varied depending on the length of the hospital stay, which ranged from 3 days to over 2 weeks. By achieving zero hospitalizations over the 12-month follow-up, the intervention resulted in considerable direct cost savings. Figure 3 illustrates the cost per episode of HD-CRBSI for eight episodes of patients admitted to the Royal Hospital [Table 2].

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Figure 3: The estimated cost per catheter-related bloodstream infection hospitalization episode.

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DISCUSSION

This study demonstrates that antibiotic lock therapy was associated with the absence of recurrent CRBSI in a small cohort of high-risk HD patients.

These findings are consistent with previous literature suggesting reduced infection rates with antimicrobial lock solutions.

Infections are the second leading cause of death in patients with ESKD on HD.^[14] HD-CRBSI have increased in recent years due to failed AVF/AVG and the prolonged use of tunneled catheters for more than 3 months.^[15] In our center, patients undergoing HD through a tunneled catheter represent approximately 20% of the cohort. The most common pathogenic bacteria reported to cause CRBSI are coagulase-negative Staphylococcus (especially S. epidermidis), followed by S. aureus, Candida spp., and Enterococcus.^[16] This aligns with our findings, where 75% (three out of four cases) involved Staphylococcus species. Infection risk also varies with comorbid conditions, such as diabetes mellitus, and disruptions of dermal barriers.^[16,17] All four patients in our study had diabetes, and 50% showed improved random blood sugar control after CRBSI prevention through the antibiotic lock.

The inflammatory process contributes substantially to the development of anemia in chronic HD patients by inducing unresponsiveness to erythropoiesis-stimulating agents (ESAs).^[18,19] Markers such as serum C-reactive protein (CRP), erythrocyte sedimentation rate, and serum albumin are used to assess inflammatory states and predict treatment responses.^[18,20] In our study, anemia (hemoglobin levels), CRP, and serum albumin improved in all four cases following the prevention of CRBSI. Previous research confirms that HD patients with high CRP or low albumin levels generally have lower hemoglobin levels,^[21] and the relationship between low albumin and anemia is likely linked to ESA hyporesponsiveness.^[22]

A recent longitudinal study, Dialysis Outcomes and Practice Patterns Study (DOPPS), found that acute increases in inflammation increase ESA dose requirements and the incidence of ESA hyporesponsiveness.^[23,24] In the current study, the elimination of CRBSI through antibiotic catheter locks led to a marked decrease in the required EPO dose for every patient. This not only reduced medication costs but also mitigated the potential hazards associated with high-dose EPO therapy.

Adequate HD is typically defined by a urea reduction ratio (URR) of at least 65%, with values below 65% associated with increased morbidity and mortality.^[25,26] It has been shown that for every 5% increase in URR, the mortality rate decreases by up to 11%.^[27] Following the intervention in our study, dialysis adequacy URR increased by approximately 5% across all four cases.

Furthermore, the antibiotic catheter lock protocol completely prevented hospitalizations in these four high-risk patients over a 1-year period. A 2013 meta-analysis estimated the healthcare cost per episode of central venous catheter-related bacteremia in the USA at $45,814, constituting a massive financial burden.^[28] In Oman, our data indicate an average cost of $6,000 per HD-CRBSI admission. Preventing these episodes yields substantial direct financial savings, in addition to the indirect savings from reduced EPO usage and the unquantifiable benefit of improved patient quality of life.

CONCLUSION

Antibiotic lock therapy was associated with a reduction in CRBSI in this small cohort of HD patients with a history of recurrent infections. Over a 1-year follow-up period, the intervention resulted in zero incidences of catheter-related infections, hospitalizations, and readmissions. One patient passed away in 2024 due to cardiac arrest after receiving a HeRO graft and catheter removal. The remaining three patients have continued to experience zero catheter infections to date. Furthermore, the prevention of chronic inflammation led to a marked decrease in required EPO doses. This approach offers substantial cost reductions, both directly through the prevention of hospital admissions and indirectly through decreased medication requirements.