Serum bilirubin concentration is associated with EGFR and urinary albumin excretion in patients with type 1 diabetes mellitus

Aims Although relationships of serum bilirubin concentration with estimated glomerular filtration rate (eGFR) and urinary albumin excretion (UAE) in patients with type 2 diabetes have been reported, whether such relationships exist in patients with type 1 diabetes is unknown. Methods A total of 123 patients with type 1 diabetes were investigated in this cross-sectional study. The relationship between bilirubin (total and indirect) concentrations and log(UAE) as well as eGFR was examined by Pearson's correlation analyses. Multivariate regression analyses were used to assess the association of bilirubin (total and indirect) with eGFR as well as log(UAE). Results A positive correlation was found between serum bilirubin concentration and eGFR; total bilirubin (r = 0.223, p = 0.013), indirect bilirubin (r = 0.244, p = 0.007). A negative correlation was found between serum bilirubin concentration and log(UAE); total bilirubin (r = - 0.258, p = 0.005), indirect bilirubin (r = - 0.271, p = 0.003). Multivariate regression analyses showed that indirect bilirubin concentration was an independent determinant of eGFR and log(UAE). Conclusions Bilirubin concentration is associated with both eGFR and log(UAE) in patients with type 1 diabetes. Bilirubin might have a protective role in the progression of type 1 diabetic nephropathy.