Change in vascular access and hospitalization risk in long-term hemodialysis patients

Abstract

Background and objectives: Conversion from central venous catheters to a graft or a fistula is associated with lower mortality risk in long-term hemodialysis (HD) patients; however, a similar association with hospitalization risk remains to be elucidated.

Design, setting, participants, & measurements: We conducted a prospective observational study all maintenance in-center HD patients who were treated in Fresenius Medical Care, North America legacy facilities; were alive on January 1, 2007; and had baseline laboratory data from December 2006. Access conversion (particularly from a catheter to a fistula or a graft) during the 4-month period from January 1 through April 30, 2007, was linked using Cox models to hospitalization risk during the succeeding 1-year follow-up period (until April 30, 2008).

Results: The cohort (N = 79,545) on January 1, 2007 had 43% fistulas, 29% catheters, and 27% grafts. By April 30, 2007, 70,852 patients were still on HD, and among 19,792 catheters initially, only 10.3% (2045 patients) converted to either a graft or a fistula. With catheters as reference, patients who converted to grafts/fistulas had similar adjusted hazard ratios (0.69) as patients on fistulas (0.71), while patients with fistulas/grafts who converted to catheters did worse (1.22), all P < 0.0001.

Conclusions: Catheters remain associated with the greatest hospitalization risk. Conversion from a catheter to either graft or fistula had significantly lower hospitalization risk relative to keeping the catheter. Prospective studies are needed to determine whether programs that reduce catheters will decrease hospitalization risk in HD patients.

Figure 1.

Vascular access type as of January 1, 2007, and associated 1-year hospitalization risk from all causes (N = 79,545), using standard Cox models (A) and time-dependent Cox models (B). The black line tracks the distribution of patients by vascular access category. Case mix includes age, gender, race, diabetes, and vintage, whereas lab includes eKt/V, albumin, hemoglobin, and phosphorus.

Figure 2.

Time-dependent Cox models depicting vascular access type as of January 1, 2007 (N = 79,545), and associated 1-year hospitalization risk from vascular access–related issues (A) and sepsis/bacteremia (B). The black line tracks the distribution of patients by vascular access category. Case mix includes age, gender, race, diabetes, and vintage, whereas lab includes eKt/V, albumin, hemoglobin, and phosphorus.

Figure 3.

Changes in access type (or maintaining the same access type during 4 months between January 1 and April 30, 2007) in all surviving patients (N = 70,852) and subsequent 1-year hospitalization risks from all causes (A); vascular access–related issues (B); and sepsis/bacteremia (C). The black line tracks the distribution of patients by vascular access category. Case mix includes age, gender, race, diabetes, and vintage, whereas lab includes eKt/V, albumin, hemoglobin, and phosphorus.