Abstract 94: A study of the correlation between carotid intima-media thickness and thyroid profile in patients with subclinical hypothyroidism

Objective: In patients without cardiovascular disease (CVD), subclinical hypothyroidism (SCH) as a cardiovascular risk is controversial. In this study we aim to correlate carotid intima-media thickness (CIMT) as a CV risk marker with thyroid profile in patients with subclinical hypothyroidism. Methods: This was a cross-sectional study with 79 newly diagnosed SCH patients (defined as TSH: 4.3-10 mIU/L with FT4: 1-1.6 ng/dL), in which 53 had no comorbidities, while 26 patients had both hypertension and type 2 diabetes mellitus (T2DM). We also included 53 healthy participants (defined as TSH: 0.5- 4.2 mIU/L with FT4: 1-1.6 ng/dL). BMI, pulse, BP, TSH, FT4, lipid profile and CIMT of both carotid arteries were done in all participants. Statistical data were analysed using XLSTAT software with t test and Pearson correlation for continuous variables and p value < 0.05 were considered significant. Results: The mean TSH values among euthyroid controls, SCH with comorbidities and SCH without comorbidities were 2.56 ± 10.5 mIU/L, 7.08 ± 1.31 mIU/L and 7.17 ± 1.36 mIU/L respectively. There was no statistically significant difference in mean TSH value in between the two SCH groups. The patients with SCH without comorbidities had higher CIMT mean values than euthyroid participants which was statistically significant. The mean difference of left and right sided CIMT between these two groups was -0.088 mm (p < 0.001) and - 0.094 mm (p < 0.001) respectively. On the other hand, although patients with SCH with comorbidities had higher CIMT mean values than patients without comorbidities, it was not found to be statistically significant. The mean difference of left and right sided CIMT in between these two groups was -0.051 mm (p = 0.089) and -0.055 mm (p = 0.071) respectively. Age, TSH, total cholesterol and LDL were found to correlate significantly with CIMT in patients of SCH without comorbidities. Conclusion: CIMT as surrogate marker for CVD was found to be increased in SCH patients without prior CVD. Further large sized and long-term outcome studies are needed to establish SCH as risk factor in patients without CVD. Whether therapy with levothyroxine will improve CIMT and decrease CVD risk needs further evaluation.