Tubular markers are associated with decline in kidney function in proteinuric type 2 diabetic patients

Our aim was to investigate u-NGAL, u-KIM1 and p-FGF23 and prediction of decline in kidney function in type 2 diabetic patients with proteinuria. Methods: We performed a follow-up study, follow-up median (range) 3.5 (1-5) years. At baseline u-NGAL, u-KIM1 and p-FGF23 (ELISA) was measured and patients were followed yearly with estimated(e)-GFR (MDRD) and u-albumin. Results: We included 177 patients (44 women), mean age (SD) 59 (9) years. eGFR 90 (24) ml/min/1.73 m(2) at baseline, u-albumin: median (interquartile range) 104 (39-238) mg/24 h. Patients with levels of u-KIM1 in the highest quartile had a greater decline in eGFR than patients with the lowest quartile 6.0 (5.4) versus 3.2 (5.5) ml/min/1.73 m(2) per year (p = 0.02). u-NGAL in the highest versus lowest quartile eGFR decline: 5.1 (4.7) and 2.8 (7.1) ml/min/1.73 m(2) per year (p = 0.07). Higher values of u-NGAL and u-KIM1 were associated with enhanced decline in eGFR (R = 0.16 and R = 0.19, p < 0.05), however not after adjustment for progression promoters. p-FGF23 was not predictive of decline in eGFR. Conclusion: Higher levels of markers of tubular damage are associated with a faster decline in eGFR. However, since this is not independent of known progression promoters, measurement of tubular markers does not give additional prognostic information. (C) 2012 Published by Elsevier Ireland Ltd.