Abstract:Objective To investigate the correlation between the free triiodothyronine (FT3)/free thyroxine (FT4) ratio and the overall burden of cerebral small vessel disease (CSVD) in patients. Methods A retrospective analysis was conducted on the electronic medical records of 251 patients with CSVD who were hospitalized in the Department of Neurology at Nanjing Jiangbei Hospital from August 2020 to July 2022. Based on the results of cranial magnetic resonance imaging, the subjects were scored for overall CSVD burden and divided into a mild group (125 cases) and a severe group (126 cases). Spearman correlation analysis and logistic regression analysis were used to explore the correlation between indices such as FT3/FT4 ratio and thyroid-stimulating hormone (TSH) with the overall burden of CSVD. Results The FT3/FT4 ratio was higher in the severe group compared to the mild group ［（0.27±0.04）vs (0.20±0.04),t=14.388, P＜0.01］. Spearman correlation analysis indicated that there was a significant positive correlation between the FT3/FT4 ratio and TSH with the overall burden of CSVD (r=0.600, 0.200; P＜0.01); logistic regression analysis suggested that an elevated FT3/FT4 is an independent risk factor for increased overall burden of CSVD (OR=2.706,95%CI: 2.161-3.508, P＜0.01). Conclusion There is a correlation between TSH, FT3/FT4 ratio and the overall burden of CSVD, with elevated FT3/FT4 ratio being an independent risk factor for increased overall burden of CSVD.