Abstract:Objective To investigate the impacts of subclinical hypothyroidism(SCH) on type 2 diabetes mellitus（T2DM）and its common chronic complications. Methods A total of 321 T2DM patients with complete clinical data treated in Northern Theater General Hospital from January 2018 to December 2019 were divided into simple T2DM group (n=264) and T2DM with SCH group (n=57) according to whether they were complicated with subclinical hypothyroidism. The general clinical data, biochemical indexes and common chronic complications of diabetic retinopathy (DR), diabetic kidney disease(DKD) and diabetic foot disease(DFD) were retrospectively analyzed. Results The levels of total cholesterol, triglyceride, urinary albumin/creatinine ratio (UACR),estimated glomerular filtration rate (eGFR) and ankle brachial index (ABI) in T2DM with SCH group were significantly lower than those in alone T2DM group (all P<0.05), and the prevalence of hypertension,DR,DKD and DFD was significantly higher than that in alone T2DM group (P<0.05). Multivariate logistic regression analysis showed that high thyroid stimulating hormone level was the independent risk factor for DKD （OR=1.087,95%CI:1.022-1.155） and for DFD （OR=1.071,95% CI: 1.001-1.146),but was not for diabetic retinopathy. Conclusion In newly diagnosed patients with type 2 diabetes, thyroid function test should be carried out as soon as possible and regularly so as to confirm subclinical hypothyroidism as soon as early in order to reduce the occurrence and development of common chronic complications of diabetes.