ARTERIOVENOUS FISTULA CREATION MAY SLOWDOWN THE DECLINE IN ESTIMATED GLOMERULAR FILTRATION RATE IN PATIENTS WITH DIABETIC NEPHROPATHY

Arteriovenous fistula (AVF) creation should be considered when the glomerular filtration rate (GFR) falls below 15–20 mL/min/1.73 m2, as recommended by the Kidney Disease: Improving Global Outcomes guidelines. Pre-dialysis AVF creation is recommended to allow its maturation, thereby reducing catheter-related complications. In clinical practice, a slower decline in estimated GFR (eGFR) is occasionally observed after AVF creation. While some studies have proposed mechanisms such as increased renal blood flow due to increased cardiac output or reduced renal congestion to explain this observation, others failed to demonstrate the renal protective effect of AVF creation. Moreover, factors associated with the post-AVF eGFR slope remain unclear. Therefore, we examined factors associated with changes in the eGFR slope by comparing the eGFR slope before and after AVF creation.

This was a single-center retrospective cohort study including patients with chronic kidney disease (CKD) who initiated dialysis between April 2016 and March 2023 in Oita University Hospital and had available eGFR data for at least 30 days after the pre-dialysis AVF creation. The observation period was from 12 months before the AVF creation until the day of dialysis initiation. The eGFR slopes before and after AVF creation were estimated using a linear regression model. Patients were classified into the improvement and non-improvement groups based on the change in the eGFR slope after AVF creation, and clinical characteristics, comorbidities, laboratory data, medications, and echocardiographic parameters were compared using logistic regression analysis.

A total of 105 patients were included (mean age, 66.2 ± 13.8 years; 70% male). The mean eGFRs at AVF creation and dialysis initiation were 8.9 ± 1.9 and 6.5 ± 2.1 mL/min/1.73 m2, respectively. The mean pre-AVF and post-AVF eGFR slopes were −11.9 ± 10.0 and −7.6 ± 7.6 mL/min/1.73 m2/year, respectively, revealing a significant improvement after AVF creation (+4.2, 95% confidence interval +2.2 to +6.3, p < 0.001). Patients with diabetic nephropathy (n = 45, 42.8%) exhibited a significant improvement in eGFR slope (−17.9 to −8.0 mL/min/1.73 m2/year, p < 0.001), whereas those with other underlying kidney diseases did not. The improvement group (n = 70) was significantly younger (63.9 vs. 70.8 years), was more diabetic (66% vs. 37%), had more proteinuria before AVF creation (5.76 vs. 3.95 g/g creatinine), had higher in eGFR at dialysis initiation (6.9 vs. 5.8 mL/min/1.73 m2), and had longer median time to dialysis initiation (150 vs. 89 days) than the non-improvement group (n = 35). No significant factors associated with eGFR slope improvement were identified in multivariate analysis.

The eGFR slope was significantly improved after AVF creation, particularly in patients with diabetic nephropathy, a notable finding given that diabetic nephropathy is typically characterized by the rapid progression of CKD. Our findings suggest that AVF creation might be associated with the preservation of renal function, potentially contributing to delayed dialysis initiation. However, we did not identify specific factors associated with the improvement in eGFR slope, and further prospective studies are necessary to confirm the mechanisms proposed in previous studies, focusing on hemodynamic and volume-related parameters.