High atherogenic index of plasma in subclinical hypothyroidism: Implications in assessment of cardiovascular disease risk

BACKGROUND A controversy exists regarding the association between subclinical hypothyroidism (SH) and dyslipidemia. Moreover, studies on lipid ratios and atherogenic index of plasma (AIP) in SH are rare, particularly in the Indian scenario. AIM This study aimed to investigate abnormalities in conventional lipid profile, lipid ratios, and AIP in SH and attempted to correlate thyroid stimulating hormone (TSH) and AIP in SH. MATERIALS AND METHODS In this retrospective analysis of patient records of SH subjects and euthyroid subjects, age, free triiodothyronine, free thyroxine, TSH, total cholesterol, triglycerides, high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol, lipid ratios, and AIP were compared between the two groups. The correlation of TSH and AIP in SH was studied. Spearman's correlation, Mann-Whitney U-test and logistic regression analysis were performed. RESULTS Triglyceride, triglyceride/HDL-C, and AIP were significantly higher in SH as compared to euthyroid group, but there was no correlation between TSH and AIP in SH. AIP emerged as the significant single factor associated with SH in multiple logistic regressions. CONCLUSION The positive association of dyslipidemia and SH indicates a need for regular screening of these patients to enable early diagnosis and treatment of dyslipidemia. Even in patients who have a normal conventional lipid profile, lipid ratios, and AIP have to be calculated for better assessment of atherogenic risk.