VASCULAR ACCES – RELATED MORBIDITY IN HEMODIALYSIS PATIENTS IN URUGUAY

Between the three major types of hemodialysis (HD) vascular access, hemodialysis catheters (CAT), arteriovenous grafts and arteriovenous fistulas (AVFs), the last are the most recommended for end stage kidney disease (ESKD) patients on hemodialysis due to their benefits, while catheters are associated with high morbidity and mortality due to infection, lower quality of dialysis and the development of vein stenosis. The aim of this research is to analyze vascular access – related morbidity in hemodialysis patients in Uruguay (UY). 

We retrospectively analyzed a HD cohort of prevalent patients on 2022 in UY. Data was extracted from the Uruguayan Dialysis Registry (UDR), a mandatory registry that includes information of all patients receiving chronic dialysis treatment in the country. Vascular access was divided into catheters (CAT) or arteriovenous grafts or fistulas (AV). Vascular access – related hospitalizations were classified into infectious or non-infectious (thrombosis, bleeding, stenosis, aneurysm or steal syndrome) and 4 categories were established: CAT-inf, CAT-non inf, AV-inf, AV-non inf. Those complications that did not require hospital admission were not included. Mean differences were estimated using χ2 or Student’s t test. Statistical significance was established as p < 0.05. To quantify morbidity, we calculated the rate of admissions by 1000 HD sessions. 

A total of 3,472 patients (60.1% male; 66.2% diabetes) were included with a mean age of 62.9 years (SD ± 16.2). During 2022, a total of 390,920 chronic HD sessions were performed, on 64.4% of them the vascular access was an AV graft or fistula and on 35.6% was a CAT. We analyzed 716 vascular access – related admissions (in 589 patients) and 69.7% of them were nonrelated to infection. The rate of admissions related to AVFs was 2,18/1000 HD session (95% CI: 2,00/1000 –2,36/1000) and the rate of admissions related to CAT was 1,21/1000 HD session (95% CI: 1,04/1000 –1,41/1000). According with the 4 categories created the hospitalizations due to an AV-non inf complication were the most frequent with a rate of 1,82/1000 HD session (table 1). Although the infection rate complications of CAT are the triple of AVFs, the overall rate is lower due to a lower frequency of mechanical complications. When comparing patients who required vascular access related – admission with those who did not, age was similar (63.0 vs 62.7 years; p=ns) but diabetes was more frequent on the first group (70.5% vs 60.4%; p=0.02).

Table 1 Title: Table 1. Vascular access- related morbidity rate.

Footnote: AV-inf: arteriovenous graft or fistula infections; AV-non inf: arteriovenous graft or fistula non infection; CAT-inf: catheter related infections; CAT-non inf: catheter related non infection.

We found the results of the study surprising; we did not expect a higher rate of complications in patients with fistula compared to catheter. By far, mechanical complications of AVFs were responsible for most hospital admissions. The explanation for this observation is probably multifactorial and is related to the comorbidities of the assisted population and a decrease in infectious complications of catheters due to the improvement of their characteristics. An analysis of the changes in the trend over the last years would be of interest for a better understanding of the complications associated with vascular access.