Supplementary Material for: Factors Affecting the Decision to Initiate Dialysis: A National Survey of United States Nephrologists

Introduction
The percentage of patients initiating dialysis at an estimated glomerular filtration rate (eGFR) ≤9 mL/min/1.73 m2 decreased between 2000 and 2018 in the United States. Clinical practice guidelines recommend basing the decision to initiate dialysis primarily on uremic signs and symptoms, rather than on a particular level of kidney function. However, what signs and symptoms currently practicing nephrologists consider “uremic”, how they weigh eGFR and other factors in the decision to initiate dialysis have not been reported.

Methods
The study was an online survey of 255 United States nephrologists, conducted between August and October 2021.

Results
Nearly half of respondents (49.8%) had an absolute lower eGFR (8.4 (95% CI: 7.6, 9.2) mL/min/1.73 m2) at which they would initiate dialysis in an asymptomatic patient. The top 5 symptoms that would trigger a recommendation to initiate dialysis were loss of appetite/nausea/vomiting (17%), low eGFR (10%), shortness of breath (10%), declining physical ability/function (9%), and generalized weakness (9%). Poor nutritional status and physical function decline were considered very important in the decision to initiate dialysis by 64% and 55% of respondents, respectively. Nephrologists surveyed significantly shortened the time to dialysis initiation in response to declining physical function in an otherwise asymptomatic (hypothetical) patient.

Conclusions
Nearly half of nephrologists sometimes based their decision to initiate dialysis on eGFR alone. The eGFR threshold at which they did so was lower than has been examined in randomized controlled trials of dialysis initiation. Initiatives designed to safely delay dialysis through aggressive medical management could focus on modifiable factors that are the most important drivers of the decision to initiate dialysis.