Importance of age and timing of referral when initiating dialysis.

Background: Mortality of patients > 75 years of age initiating dialysis is high. Late referral to a nephrologist prior to dialysis initiation is associated with poor outcomes. Herein, we report the outcomes of patients initiating dialysis according to their age and timing of referral.

Methods: We reviewed a prospective cohort of patients initiating dialysis from 2000 to 2022 at a single university center. Primary outcome was one-year all-cause mortality. Secondary outcomes were overall all-cause mortality and one-year hospitalization days. Late referral was defined as dialysis initiation < 1 month after a first consultation with a nephrologist.

Results: We included 906 patients, including 246 (27%) aged over  75 years. Late referral was more common in elderly patients compared to younger ones, with rates of 26% and 34%, respectively (p = 0.027). Regarding one-year mortality, considering patients aged over 75 years with early referral as the reference, patients aged > 75 years with late referral were at higher risk (Hazard Ratio [HR] 2.30, p = 0.001), while patients aged < 75 years with either early or late referral were at similar risk. Regarding overall mortality, patients aged > 75 years with late referral were at higher risk (HR 1.56, p = 0.002), while patients aged < 75 years with either early (HR 0.65, p < 0.001) or late referral (HR 0.62, p = 0.001) were at lower risk. Finally, patients aged over 75 years with late referral had more hospitalization days per year (coef 0.09, p < 0.001), while patients < 75 years with either early (coef - 0.07, p < 0.001) or late referral (coef - 0.05, p < 0.001) had fewer hospitalization days per year.

Conclusions: Late referral of elderly patients prior to dialysis initiation is common and adversely associated with short- and long-term mortality as well as hospitalization days. Conversely, early referral of elderly patients is associated with a favorable short-term prognosis that is comparable to that of younger patients.