T2DM patients with subclinical hypothyroidism face elevated macrovascular complications: Study

A new study published in the journal of Cureus showed that the risk of macrovascular problems was 6.75 times greater for diabetic individuals with severe subclinical hypothyroidism (SCH) and 4.35 times higher for the patients with mild SCH.

The prognosis of people with type 2 diabetes is worse when this condition coexists with other thyroid conditions, like subclinical hypothyroidism (SCH). Therefore, it is critical to determine the relationship between macrovascular problems in patients with type 2 diabetes and thyroid function, namely thyroid-stimulating hormone (TSH).

Gaining a comprehensive understanding of TSH and the distinctions and relationships between T2DM patients with SCH and other complications is vital because it will close the knowledge gaps on SCH-T2DM comorbidity and offer vital details about clinical significance, risk factors, and interventions. In addition to examining important metabolic, demographic, and clinical characteristics in T2DM patients with SCH, this study attempts to investigate the relationship between different levels of thyroid-stimulating hormone and the risk of macrovascular problems.

The data from 2017 to 2023 was gathered for a retrospective analysis at Dalian Medical University's Second Affiliated Hospital. Based on their TSH values, 305 patients were split into 3 groups where T2DM moderate SCH (TSH 7.0-9.9 mIU/L), T2DM severe SCH (TSH levels of 10.0 mIU/L or more), and T2DM mild SCH (TSH 4.34-6.9 mIU/L).

For continuous data, one-way analysis of variance (ANOVA) was employed, whilst the chi-square test was utilized for categorical variables. Binary logistic regression analysis, both univariate and multivariate, was used to assess the risk of macrovascular problems. Furthermore, p <0.05 was chosen as the threshold for statistical significance.

Macroscopic problems were most common in patients with severe SCH (19, 90.5%), moderate SCH 38 (80.9%), and mild SCH 142 (59.9%) (p < 0.001). According to multivariate analysis, the risk of macrovascular complications was 4.35 times higher in moderate SCH and 6.08 times higher in severe SCH than in mild SCH.

Macrovascular problems were significantly predicted by male sex, severe SCH, and age group 65 and older. Severe SCH was especially linked to coronary artery disease (CAD) and peripheral arterial disease (PAD). Overall, patients with type 2 diabetes who have severe or moderate SCH are far more likely to get macrovascular problems, including CAD and PAD. 

Source:

Mahmud, N. M. M., Jagdewsing, D. R., Ji, X., Harine, I., Adjibou, B., Fahmy, N. S. C., Juby, T., Shuvo, R. I., Alam, A., & Sarmin, S. (2025). Association between different thyroid-stimulating hormone levels and macrovascular complications in subclinical hypothyroidism patients with type 2 diabetes mellitus. Cureus. https://doi.org/10.7759/cureus.79186