Hemodialysis vascular access modifies the association between dialysis modality and survival

Abstract

Several comparisons of peritoneal dialysis (PD) and hemodialysis (HD) in incident patients with ESRD demonstrate superior survival in PD-treated patients within the first 1 to 2 years. These survival differences may be due to higher HD-related mortality as a result of high rates of incident central venous catheter (CVC) use or due to an initial survival advantage conferred by PD. We compared the survival of incident PD patients with those who initiated HD with a CVC (HD-CVC) or with a functional arteriovenous fistula or arteriovenous graft (HD-AVF/AVG). We used multivariable piece-wise exponential nonproportional and proportional hazards models to evaluate early (1 year) mortality as well as overall mortality during the period of observation using an intention-to-treat approach. We identified 40,526 incident adult dialysis patients from the Canadian Organ Replacement Register (2001 to 2008). Compared with the 7412 PD patients, 1-year mortality was similar for the 6663 HD-AVF/AVG patients but was 80% higher for the 24,437 HD-CVC patients (adjusted HR, 1.8; 95% confidence intervals [CI], 1.6 to 1.9). During the entire period of follow-up, HD-AVF/AVG patients had a lower risk for death, and HD-CVC patients had a higher risk for death compared with patients on PD. In conclusion, the use of CVCs in incident HD patients largely accounts for the early survival benefit seen with PD.

Figures

Figure 1.

Survival curves for HD-CVC (short-dashed line), HD-AVF/AVG (long-dashed line), and PD (solid line) demonstrate higher 1-year mortality in HD-CVC patients. (A) Unadjusted. (B) Adjusted on the basis of a stratified Cox proportional Hazards model stratified by HD-CVC, PD, and HD-AVF/AVG and adjusted for age, race, gender, era of dialysis initiation, end-stage renal disease comorbidity index, primary renal diagnosis, serum albumin, eGFR, province of treatment, and late referral.

Figure 2.

Hemodialysis vascular access affects the association between modality and survival in selected subgroups. *P value for interaction (int). The models were adjusted for age, race, gender, era of dialysis initiation, ESRD comorbidity index, primary renal diagnosis, serum albumin, estimated GFR, province of treatment and late referral.