Trajectories of kidney function decline in the 2 years before initiation of long-term dialysis

Abstract

Background: Little is known about patterns of kidney function decline leading up to the initiation of long-term dialysis.

Study design: Retrospective cohort study.

Setting & participants: 5,606 Veterans Affairs patients who initiated long-term dialysis in 2001-2003.

Predictor: Trajectory of estimated glomerular filtration rate (eGFR) during the 2-year period before initiation of long-term dialysis.

Outcomes & measurements: Patient characteristics and care practices before and at the time of dialysis initiation and survival after initiation.

Results: We identified 4 distinct trajectories of eGFR during the 2-year period before dialysis initiation: 62.8% of patients had persistently low level of eGFR < 30 mL/min/1.73 m2 (mean eGFR slope, 7.7 ± 4.7 [SD] mL/min/1.73 m2 per year), 24.6% had progressive loss of eGFR from levels of approximately 30-59 ml/min/1.73 m2 (mean eGFR slope, 16.3 ± 7.6 mL/min/1.73 m2 per year), 9.5% had accelerated loss of eGFR from levels > 60 mL/min/1.73 m2 (mean eGFR slope, 32.3 ± 13.4 mL/min/1.73 m2 per year), and 3.1% experienced catastrophic loss of eGFR from levels > 60 mL/min/1.73 m2 within 6 months or less. Patients with steeper eGFR trajectories were more likely to have been hospitalized and have an inpatient diagnosis of acute kidney injury. They were less likely to have received recommended predialysis care and had a higher risk of death in the first year after dialysis initiation.

Conclusions: There is substantial heterogeneity in patterns of kidney function loss leading up to the initiation of long-term dialysis perhaps calling for a more flexible approach toward preparing for end-stage renal disease.

Figure 1. eGFR trajectories and 95% confidence intervals defined by trajectory modeling. Dotted lines denote 95% confidence intervals

Trajectory Group 1 (persistently low levels of eGFR): 63% of patients with a mean probability of assignment 0.88 (±0.24) Trajectory Group 2 (progressive loss of eGFR): 25% of patients with a mean probability of assignment 0.86 (±0.27) Trajectory Group 3 (accelerated loss of eGFR): 9% of patients with a mean probability of assignment 0.91 (±0.25) Trajectory Group 4 (catastrophic loss of eGFR): 3% of patients with a mean probability of assignment 0.99 (±0.11)

Figure 2

Scatter plots of all eGFR measurements during the two year period before dialysis initiation for 25 randomly selected members of each trajectory group

Figure 3

Individual eGFR trajectories for 10 randomly selected members of each trajectory group

Figure 4

Kaplan-Meier curves showing survival after dialysis initiation by trajectory group