Urinary Melamine Levels and Progression of CKD.

Abstract

CKD is a global public health problem. Some cross-sectional studies have associated environmental melamine exposure with kidney diseases, but evidence is limited. We conducted this prospective cohort study to enroll patients with eGFR≥30 ml/min per 1.73 m2 in 2006-2010. Urinary corrected melamine levels (ratio of urinary melamine to urinary creatinine) were measured by liquid chromatography/tandem mass spectrometry at enrollment. Kidney outcomes included doubling of serum creatinine levels, eGFR decline >3 ml/min per 1.73 m2 per year, and 30% decline in eGFR in the first 2 years. Subjects were followed until targeted kidney outcomes, cancer, death, last contact, or the end of observation in December 2016. In a total of 293 subjects, the median urinary corrected melamine level was 0.97 (interquartile range, 0.43-2.08) μg/mmol. Over a median follow-up period of 7.0 years, serum creatinine levels doubled in 80 subjects (27%). Subjects in the highest tertile of urinary melamine level 12.70 μg/mmol) had a 2.30 (95% confidence interval, 1.25 to 4.23; P<0.01) hazard risk for doubling of serum creatinine compared with those in the lowest tertile (0.02-0.58 μg/mmol). Similar significant dose-response results were found in eGFR decline >3 ml/min per 1.73 m2 per year and 30% decline in eGFR in the first 2 years. Urinary melamine level is significantly associated with kidney function deterioration in patients with early-stage CKD.