Context: The treatment of diabetic nephropathy (DN) is still quite limited. DN remains poorly understood due to the complexity of and differences in its etiology. Therefore, potential biomarkers for diagnosis and targeted treatments are urgently needed.
Objective: The study aimed to analyze the associations between circulating total bile acid (TBA) levels and the risk of DN in Chinese patients with type 2 diabetes mellitus (T2DM) and to determine the differences in the TBA levels of males and females, including pre- and postmenopausal women, to find clues for the screening of DN.
Design: The research team performed a retrospective study.
Setting: The study took place at the Second Affiliated Hospital at the School of Medicine of Zhejiang University in Zhejiang, China.
Participants: Participants were 1785 T2DM patients admitted to the hospital between April 2008 and November 2013.
Groups: The research team separated participants into three groups: (1) the normoalbuminuria or normal group, with a UACR <30 mg/g·Cr (2) the microalbuminuria (MAU) group, with a UACR of 30-299 mg/g·Cr; and (3) the macroalbuminuria (MAC) group, with a UACR of ≥300 mg/g·Cr.
Outcome measures: Between the three groups, the research team compared: (1) the demographic and clinic characteristics of the normal, MAU, and MAC groups; (2) TBA distribution by age; (3) TBA distribution by gender; and (4) TBA quartiles. The team also examined the associations between TBA and albuminuria, identifying the odds ratios (OR) and relevant 95% confidence intervals (CI) using multiple logistic regression.
Results: The study found that: (1) the MAC group's TBA was significantly lower than those of the normal and MAU groups; (2) the TBA of postmenopausal women was significantly higher than that of premenopausal women; (3) the incidence of MAC was obviously increased with TBA levels; (4) the risks for MAU group didn't change significantly with increasing TBA levels; (5) the MAC group's odds ratios (ORs) were 0.61 between Q2 and Q1, 0.44 between Q3 and Q1, and 0.38 between Q4 and Q1; and (6) for men and postmenopausal women, the TBA levels of those in Q3 and Q4 might decrease the risk of MAC, whereas no such correlation existed for MAU.
Conclusions: An independent negative association exists between TBA levels and MAC in T2DM. The decrease of circulating TBA might be a prospective clinical factor for determining established DN, especially for males and postmenopausal females.