Association of antithyroid peroxidase antibodies with cardiac function in euthyroid women with type 1 diabetes mellitus - assessment with two-dimensional speckle-tracking echocardiography

Introduction: The presence of diabetes is associated with loss of cardioprotection in premenopausal women; however, the mechanisms involved remain unknown. Autoimmune factors are suspected to play a role in cardiovascular complications, especially in type 1 diabetes (T1DM). The aim of this pilot study was to explore whether antithyroid peroxidase antibody (aTPO) as a marker of increased immune activity is related to cardiac dysfunction in young, asymptomatic women with T1DM. Material and methods: Eighty-eight euthyroid women (59 with T1DM and 29 healthy controls) underwent physical examination, laboratory tests, thyroid ultrasound, and two-dimensional speckle-tracking echocardiography. According to the antiperoxidase antibodies (aTPO) titre, the T1DM women were divided into an aTPO positive (T1DM aTPO+) (n = 34) and an aTPO negative (T1DM aTPO-) (n = 25) group. The relationship between thyroid autoimmunity parameters and echocardiographic parameters was evaluated. Results: Global longitudinal strain (GLS) was slightly reduced in the T1DM aTPO+ group compared to T1DM aTPO- and significantly compared to controls (p = 0.051 and p = 0.015, respectively). Although, the lower values of longitudinal strain of left ventricular were found in the majority of segments in the T1DM aTPO+ group in comparison to T1DM aTPO- and controls, significant differences were only found in the two-chamber view (specifically in the anterior segments) between the T1DM aTPO+ and T1DM aTPO- groups (p = 0.030) and in the four-chamber view (specifically in the anterolateral segments) between the T1DM aTPO+ group and controls (p = 0.021). Echocardiographic parameters of diastolic and systolic function of both ventricles were significantly correlated with parameters of thyroid autoimmunity. A logistic regression analysis showed that Hashimoto's thyroiditis (HT) duration [odds ratio (OR): 0.997, 95% confidence interval (CI): 0.995-0.999, p = 0.008), the dose of levothyroxine (OR: 0.814, 95% CI: 0.689-0.960, p = 0.013), and reduced echogenicity on thyroid ultrasound (OR: 0.309, 95% CI: 0.120-0.793, p = 0.013) had a significant influence on reduced GLS. Conclusions: Our results suggest that coexistence of aTPO with T1DM was associated with poorer myocardial function, particularly in the anterior and anterolateral segments, which may be related to an autoimmune factor. The impaired function of these segments is probably the first sign of myocardial systolic dysfunction in women with T1DM, which needs to be confirmed in further studies. (Endokrynol Pol 2022; 73 (5): 812-822)