The longitudinal effect of subclinical hypothyroidism on urine microalbumin-to-urine creatinine ratio in patients with type 2 diabetes mellitus

BACKGROUND: In patients with diabetes mellitus, the urinary microalbumin-to-urine creatinine ratio (UACR) can not only predict the occurrence of diabetic nephropathy but also can be a risk factor for cardiovascular disease and renal function damage. Current studies on subclinical hypothyroidism (SCH) and UACR are mainly cross-sectional studies, and the results suggest that SCH is an independent risk factor for UACR. To further explore the longitudinal effect of SCH on UACR, we carried out this study. METHODS: This was a retrospective cohort study including 46 patients with type 2 diabetes mellitus and SCH in the Department of Endocrinology, The Affiliated Huai’an Hospital of Xuzhou Medical University from January 2013 to April 2018. At the same time, 96 patients with type 2 diabetes mellitus and euthyroid were chosen according to 1:2 approximately matched with age, sex and duration of diabetes mellitus. Univariate analysis, stratified analysis, and multiple linear regression analysis were used to investigate the effect of SCH on ΔUACR(ΔUACR = UACR after 1 year - baseline UACR) in patients with type 2 diabetes mellitus. RESULTS: There was no significant difference between the baseline UACR, (p > 0.05). However, the ΔUACR was significantly higher in SCH group than euthyroid group, as shown by univariate analysis, stratified analysis and multiple linear regression analysis (β:-1.071, 95% CI: − 1.713--0.428), and the difference was statistically significant (all p < 0.05). CONCLUSION: SCH is associated with an increased UACR in type 2 diabetes mellitus patients. It is necessary to screen for thyroid function in type 2 diabetes mellitus and increase the follow-up frequency of UACR in patients with SCH.