Early outcomes among those initiating chronic dialysis in the United States

Abstract

Background and objectives: Approximately one million Americans initiated chronic dialysis over the past decade; the first-year mortality rate reported by the U.S. Renal Data System was 19.6% in 2007. This estimate has historically excluded the first 90 days of chronic dialysis.

Design, setting, participants, & measurements: To characterize the mortality and hospitalization risks for patients starting chronic renal replacement therapy, we followed all patients initiating dialysis in 1733 facilities throughout the United States (n = 303,289). Mortality and hospitalizations within the first 90 days were compared with outcomes after this period, and the results were analyzed. Standard time-series analyses were used to depict the weekly risk estimates for each outcome.

Results: Between 1997 and 2009, >300,000 patients initiated chronic dialysis and were followed for >35 million dialysis treatments; the highest risk for morbidity and mortality occurred in the first 2 weeks of treatment. The initial 2-week risk of death for a typical dialysis patient was 2.72-fold higher, and the risk of hospitalization was 1.95-fold higher when compared to a patient who survived the first year of chronic dialysis (week 53 after initiation). Similarly, over the first 90 days, the risk of mortality and hospitalization remained elevated. Thereafter, between days 91 and 365, these risks decreased considerably by more than half. Surviving these first weeks of dialysis was most associated with the type of vascular access. Initiating dialysis with a fistula was associated with a decreased early death risk by 61%, whereas peritoneal dialysis decreased the risk by 87%.

Conclusions: The first 2 weeks of chronic dialysis are associated with heightened mortality and hospitalization risks, which remain elevated over the ensuing 90 days.

Figure 1.

(A) Among patients starting chronic dialysis (n = 303,289), the relative risk of death at each 1-week interval was compared with a reference group of patients who survived the first year of dialysis. The period of highest death risk occurred in the second week (relative risk [RR] = 2.86; 95% confidence interval [CI] 2.63 to 3.12; referenced to patients who survived the first year of dialysis). Patients were followed over 35,067,157 dialysis treatments for mortality outcomes. (B) Among patients starting chronic dialysis (n = 303,289), the RR of hospitalization at each 1-week interval was compared with a reference group of patients who survived the first year of dialysis. The period of highest hospitalization risk occurred in the first week (RR = 1.98; 95% CI 1.92 to 2.03; referenced to patients who survived the first year of dialysis). Patients were followed over 35,067,157 dialysis treatments for hospitalization outcomes.

Figure 2.

Adjusted relative risk of early, incident, and prevalent death by risk factor. PD, peritoneal dialysis; AVF, arteriovenous fistula; inpt, inpatient; outpt, outpatient.

Figure 2.

Adjusted relative risk of early, incident, and prevalent death by risk factor. PD, peritoneal dialysis; AVF, arteriovenous fistula; inpt, inpatient; outpt, outpatient.

Figure 3.

(A) Stratum-specific time-series curves for death by potentially treatable factors (modifiable). (B) Stratum-specific time-series curves for death by patient factors (fixed). PD, peritoneal dialysis.