Quantifying vascular access-associated excess mortality in maintenance hemodialysis patients

Area of Science:

• Nephrology
• Vascular Access Research
• Patient Outcomes

Background:

• Central venous catheters (CVCs) are frequently used for hemodialysis (HD) but are associated with increased mortality compared to arteriovenous accesses (AVAs).
• Patients requiring CVCs often present with greater comorbidity burdens, making it challenging to isolate the independent effect of access type on survival.
• Understanding the true impact of vascular access on HD patient survival is critical for optimizing treatment strategies.

Purpose of the Study:

• To evaluate the association between vascular access type (CVC vs. AVA) and mortality in incident hemodialysis patients.
• To adjust for confounding factors, including patient comorbidities, to better interpret the relationship between access type and survival.
• To quantify the survival benefit, if any, associated with AVA use compared to CVC use in the HD population.

Main Methods:

• Retrospective cohort study analyzing data from 146,967 incident HD patients (2016-2019).
• Employed multiple analytical strategies, including inverse probability treatment weighting (IPTW) and time-dependent survival analyses.
• Utilized a large North American dialysis organization's data for robust statistical power.

Main Results:

• Initiating hemodialysis with a CVC was associated with lower median survival (1,106 days) compared to an AVA (1,290 days).
• Sustained AVA use showed significantly better survival (median 1,226 days) than CVC-only use (median 448 days).
• IPTW analysis revealed AVA initiation was linked to a 25% lower mortality risk, and sustained AVA use to a 62% lower risk, with minimal differences in infection-related deaths.

Conclusions:

• Vascular access type significantly impacts survival in hemodialysis patients, with AVAs generally associated with better outcomes than CVCs.
• While AVA use appears linked to improved survival, observational data limitations prevent definitive causal attribution of the precise benefit.
• The observed excess mortality risk with CVCs may be partly explained by underlying patient health status and selection biases rather than solely the access type itself.