Timing of arteriovenous fistula creation in patients With CKD: a decision analysis

Background: The optimal time for arteriovenous fistula (AVF) referral is uncertain. Improving the timeliness of referral may reduce central venous catheter (CVC) use.

Study design: Monte Carlo simulation model.

Setting & population: Patients with chronic kidney disease (CKD) followed up in a multidisciplinary clinic, overall and stratified by age.

Model, perspective, & timeframe: Decision analysis, patient, patient's lifetime.

Intervention: AVF referral, using 1 of 2 strategies: refer when hemodialysis is anticipated to begin within a certain time frame or refer when estimated glomerular filtration rate (eGFR) drops below a certain threshold.

Outcomes: A range of values for each strategy are compared to each other with respect to incident vascular access type (AVF or CVC), percentage of patients with an unnecessary AVF creation, and life expectancy after dialysis therapy initiation.

Results: A 15-month referral time frame gave 34% with incident CVCs, 14% with unnecessary AVFs, and a life expectancy of 1,751 days. Time frames of 12-18 months performed similarly. Referral at eGFR of 20 mL/min/1.73 m(2) gave 38% with incident CVCs, 20% with unnecessary AVFs, and life expectancy of 1,742 days. Using an eGFR threshold of 15 mL/min/1.73 m(2), 10% had an unnecessary AVF. Policy performance was affected by CKD progression rate and age. For fast progressors (ΔeGFR = -7mL/min/1.73 m(2) per year), referral at eGFR of 25 mL/min/1.73 m(2) achieved a similar incident CVC percentage (~40%) as referral at 15 mL/min/1.73 m(2) in slower progressors (ΔeGFR = -2.78 mL/min/1.73 m(2) per year). For patients aged 70-80 and 80-90 years, time frames of 15-18 months yielded 16%-22% with unnecessary AVFs (vs 9%-11% in 50- to 60-year-olds); an eGFR threshold strategy of 20 mL/min/1.73 m(2) yielded 24% unnecessary AVFs in 80- to 90-year-olds versus 16% in 50- to 60-year-olds.

Limitations: Our model does not consider patients with nonlinear CKD progression or acute kidney injury. We did not include arteriovenous grafts or consider cost or quality of life.

Conclusions: In general, AVF referral within about 12 months of the estimated time to dialysis performed best among time frame strategies, and referral at eGFR < 15-20 mL/min/1.73 m(2) performed best among threshold strategies. The timing of referral should also be guided by the individual rate of CKD progression. Elderly patients with CKD could be referred later to reduce the risk of creating an AVF that is never used.