Controversies in timing of dialysis initiation and the role of race and demographics

Abstract

Dialysis remains the predominant form of renal replacement therapy in the United States, but the optimal timing for the initiation of dialysis remains poorly defined. Not only clinical factors such as signs/symptoms of uremia, co-existing cardiovascular disease, and presence of diabetes but also key demographic characteristics including age, gender, race/ethnicity, and socioeconomics have all been considered as potential modifying factors in the decision for the timing of dialysis initiation. The 2012 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline for the Evaluation and Management of chronic kidney disease (CKD) suggests that dialysis be initiated when signs/symptoms attributable to kidney failure such as serositis, acid-base or electrolyte abnormalities, pruritus, poorly controlled volume status or blood pressure, deteriorating nutritional status despite dietary intervention, or cognitive impairment are visible or noted. These signs/symptoms typically occur when the glomerular filtration rate (GFR) is in the range of 5-10 ml/minute/1.73 m(2) , although they may occur at higher levels of GFR. We review recent data on the timing of dialysis initiation, their implications for managing patients with late-stage CKD, and the important role of considering key demographics in making patient-centered decisions for the timing of dialysis initiation.

Figure 1. The mortality hazard ratios (HRs) using an extended Cox model with time-dependent effects of estimated glomerular filtration rates (eGFRs) and stratified by level of serum albumin

Models were run separately for each of 3 serum albumin groups as surrogates of general health: less than 2.5 g/dL, 2.5 to 3.49 g/dL, and 3.5 g/dL or higher. Panel A: Mortality HRs for patients with predialysis serum albumin level of less than 2.5 g/dL (n=12,040). The confidence intervals for the HRs include 1 in many instances and the effect of early start, an eGFR higher than 10 mL/min /1.73 m², is not as marked as in the higher albumin level groups. Panel B: Mortality HRs for patients with predialysis serum albumin levels of 2.5 to 3.49 g/dL (n=33,471). In this healthier, higher serum albumin group, greater initial eGFR is associated with a significant adverse effect on survival, especially with early starts, the group with an eGFR higher than 10 mL/min /1.73 m². Panel C: Mortality HRs for patients with predialysis serum albumin levels of 3.5 g/dL or higher (n=35 665). In this healthiest of the healthy cohort studied (HG), the adverse effects of early start on survival are seen, especially in the group with an eGFR of 15 mL/min /1.73 m² or higher. Error bars indicate 95% confidence intervals. To convert serum albumin to grams per liter, multiply by 10.(18)

Figure 2. Kaplan–Meier Curves for Time to the Initiation of Dialysis and for Time to Death

The data for time to the initiation of dialysis (Panel A) were censored at the time of death, transplantation, or withdrawal of consent or at the time a patient transferred to a nonparticipating hospital, emigrated, or could not be contacted. The curves for time to death (Panel B) are truncated at 7 years of follow-up and a cumulative hazard ratio of 60%.(22)