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Kidney Week

Abstract: PO2427

A Comparison of the Associations of Urine Markers with the Rate of Decline in Kidney Allograft Function

Session Information

Category: Transplantation

  • 1902 Transplantation: Clinical

Authors

  • Obi, Yoshitsugu, Obi Clinic, Osaka, Osaka, Japan
  • Ichimaru, Naotsugu, Osaka Daigaku Daigakuin Igakukei Kenkyuka Igakubu, Suita, Osaka, Japan
  • Isaka, Yoshitaka, Osaka Daigaku Daigakuin Igakukei Kenkyuka Igakubu, Suita, Osaka, Japan
  • Hamano, Takayuki, Osaka Daigaku Daigakuin Igakukei Kenkyuka Igakubu, Suita, Osaka, Japan

Group or Team Name

  • The CANDLE-KIT Trial Inverstigators
Background

Various urine markers are proposed to predict renal outcomes. However, there are few head-to-head comparison studies comparing their clinical relevance among kidney transplant recipients (KTRs).

Methods

In a prospective clinical trial, we enrolled 153 KTRs with anemia and >1-year history of transplantation across 23 facilities and followed them for 2 years. The annual change in eGFR was estimated based on mixed effects model. We then selected 102 patients who had baseline urine data on total protein, beta 2-microglobulin (β2MG), N-acetyl-beta-D-glucosaminidase (NAG), and L-type fatty acid binding protein (L-FABP). Total protein, NAG, and L-FABP were standardized according to urine creatinine concentration. We then compared the associations of the quintiles of each urine marker with annual decline in eGFR using univariate and multivariable linear regression models.

Results

Patients were 51±12 years-old and 54% were male. The median (IQR) of transplant vintage was 8 (5, 12) years, and the baseline eGFR levels were 31±11 mL/min per 1.73 m2. The annual eGFR change was -1.6±2.0 mL/min per 1.73 m2/ year. The median (IQR) urine levels of total protein, β2MG, NAG, and L-FABP at baseline were 0.3 (0.1-1.1) g/g Cr, 1535 (238-4780) μg/L, 0.06 (0.04-0.12) IU/L, and 16.7 (4.2-42.1) μg/g Cr, respectively. The higher levels of L-FABP and total protein were significantly associated with more rapid annual eGFR decline (P for trend <0.001 for both; Figure) while there was no significant association for β2MG or NAG. R2 was 0.10 (P=0.03) and 0.18 (P=0.001) for L-FABP and total protein, respectively. After adjustment for age, gender, mean arterial blood pressure, and baseline eGFR, the association remained significant for total protain but not for L-FABP (Figure).

Conclusion

Among urine markers of total protein, L-FABP, NAG, and β2MG, total protein appears to have greatest predictive value for eGFR decline among KTRs.

Associations of the quintiles of urinary markers with annual eGFR decline in the unadjusted models (left) and the multivariable adjusted models (right)

Funding

  • Commercial Support