Thyroid hormone sensitivity, insulin resistance and visceral fat area as determinants of prevalent coronary heart disease in euthyroid patients with type 2 diabetes.

BACKGROUND

Coronary heart disease (CHD) remains a leading cause of morbidity and mortality in patients with type 2 diabetes mellitus (T2DM). Whether thyroid hormone sensitivity indices add value for CHD risk stratification among euthyroid T2DM patients is unclear.

METHODS

In this retrospective study, we included 412 euthyroid adults with T2DM hospitalized at a tertiary hospital (112 with CHD and 300 without). We assessed thyroid hormone sensitivity indices (TT4RI, TFQI, TSHI and FT3/FT4 ratio), insulin resistance measures (HOMA-IR and METS-IR) and visceral fat area (VFA). Candidate predictors were screened by univariable logistic regression and collinearity diagnostics. A multivariable logistic regression model for prevalent CHD was developed using a stratified 70/30 train-validation split and evaluated with class-weighted stratified 5-fold cross-validation.

RESULTS

In univariable analyses, higher HOMA-IR, VFA, TT4RI, TSH, older age and hypertension were associated with CHD. Because TSH and TT4RI were highly collinear, TSH was excluded and TT4RI retained. In the final model, TT4RI, HOMA-IR, VFA and age remained independent predictors after accounting for hypertension. Discrimination was good (AUC 0.768 in the training set and 0.766 in the validation set; mean cross-validated AUROC 0.750 ± 0.035), with acceptable precision-recall performance (mean AUPRC 0.523 ± 0.074) and reasonable calibration.

CONCLUSION

Impaired thyroid hormone sensitivity, increased insulin resistance and greater visceral fat accumulation are independently associated with prevalent CHD in euthyroid patients with T2DM. A simple model incorporating TT4RI, HOMA-IR and VFA may help refine CHD risk stratification in this population.