Castelli risk indices as useful indicators of atherogenic risk in subclinical hypothyroidism

Introduction: Thyroid hormones play an important role in regulating lipid metabolism. Subclinical Hypothyroidism (SCH) is increased thyrotropin-stimulating hormone (TSH) with normal T3, T4 levels. SCH is associated with derangements in Lipid metabolism, indicated by elevated cholesterol, HDL cholesterol, LDL cholesterol, increased incidence of atherosclerosis, leading to Atherogenic risk in SCH. Significance of dyslipidemia in SCH remains controversial. Objectives: To quantitatively detect levels of total-cholesterol, HDL-Cholesterol, & LDL-Cholesterol and to assess lipid atherogenic risk based on Castelli risk indexes (CRI) in Subclinical Hypothyroidism. Materials and Method: 30 SCH cases compared with 30 euthyroid controls. Serum T3, T4, TSH estimated by ELISA method, Serum Total-Cholesterol, HDL-Cholesterol by enzymatic CHOD-PAP method, LDL-Cholesterol using Friedewald formula. Systolic and diastolic blood pressure was measured in all cases. Results: Serum levels of TSH (P<0.001), Total cholesterol (p<0.001), LDL Cholesterol (P<0.001), CRI-I (TC/HDL) (p<0.001) and CRI-II (LDL/HDL) (p<0.001) Systolic & diastolic blood pressure (P<0.001) showed significant increase. No significant change in levels of serum T3, T4, HDL-Cholesterol. Individual analysis revealed that the percentage change was higher for TSH and CRI. Conclusion: Results contribute to high atherogenic risk as indicated by CRI. So CRI can be used as better indicator of dyslipidemia as compared to isolated lipid profile parameters and highlights cardiovascular risk in SCH.