Associations of lipid-related parameters and indices with TSH-defined hypothyroid status in patients with Hashimoto’s thyroiditis: a retrospective cross-sectional study

Objective To examine the associations of eight lipid-related parameters and indices with thyroid-stimulating hormone (TSH)-defined hypothyroid status in patients with Hashimoto’s thyroiditis (HT). Methods This retrospective cross-sectional study included 422 patients with HT. Hypothyroid status was defined as TSH ≥4.5 mIU/L. Associations were estimated using multivariable logistic regression adjusted for age, sex, and laboratory-derived diabetes status. Secondary analyses distinguished non-hypothyroid status, a subclinical hypothyroid pattern, and an overt hypothyroid pattern according to TSH and free thyroxine levels, and analyzed TSH as a continuous outcome. P values were adjusted using the Benjamini-Hochberg false discovery rate procedure. Results Among the 422 patients, 221 had TSH-defined hypothyroid status and 201 had non-hypothyroid status. All eight parameters and indices were positively associated with hypothyroid status after FDR correction (q=0.002-0.036). NHHR showed the largest standardized OR point estimate (OR = 1.70, 95% CI: 1.28-2.25). In the common complete-case sample of 404 patients, seven associations remained statistically significant, whereas the association for TG was weaker (q=0.059). The hypothyroid-status group comprised 173 patients with a subclinical hypothyroid pattern and 48 with an overt hypothyroid pattern. All eight measures were associated with the overt pattern, whereas only NHHR remained associated with the subclinical pattern after FDR correction. Six measures were also associated with higher TSH when TSH was analyzed continuously. In exploratory analyses of NHHR, AIP, and TyG, no significant interactions were found by sex, age group, or laboratory-derived diabetes status. Conclusion In patients with HT, all eight lipid-related parameters and indices were positively associated with TSH-defined hypothyroid status. The associations were more consistent for the overt hypothyroid pattern; after FDR correction, only NHHR remained associated with the subclinical hypothyroid pattern.