Thyroid stimulating hormone and free triiodothyronine are valuable predictors for diabetic nephropathy in patient with type 2 diabetes mellitus.

BACKGROUND: Diabetes seriously threatens human health, and diabetic nephropathy (DN) is one of the serious diabetic complications. Therefore, it is valuable to predict the occurrence of DN early. This study aims to evaluate the predicting significance of thyroid hormones for DN. METHODS: A total of 301 type 2 diabetes mellitus (T2DM) patients were enrolled. Thyroid hormones before treatment were measured, and the risk factors and their predicting significance for T2DM and DN were assessed. RESULTS: The results indicated that there was no statistical difference in any investigated variable between controls and patients without complications (P>0.05). However, patients with DN exhibited lower levels of triiodothyronine (T3) and free triiodothyronine (FT3), but higher levels of thyroid stimulating hormone (TSH) than T2DM patients without complications (P<0.001). Multivariate analysis did not demonstrate any thyroid hormone as the independent risk factor for T2DM without complications, but revealed increased TSH and decreased T3 and FT3 as the independent risk factors for patients with DN [odds ratio (OR): 2.087, 95% CI: 1.525-3.303; 1.335, 95% CI: 1.101-1.621; 7.414, 95% CI: 4.319-13.986; P<0.001, respectively]. The area under receiver operating characteristic (ROC) curve of TSH, FT3 and T3 was 0.850 (95% CI: 0.776-0.923), 0.824 (95% CI: 0.751-0.897), and 0.620 (95% CI: 0.515-0.725) for DN prediction. Based on their cutoff values of 1.85 mIU/L, 2.31 ng/L, and 0.61 µg/L, the sensitivity was 82%, 78%, and 64%, and the specificity was 77%, 79%, and 85%, respectively. CONCLUSIONS: Our findings suggest that TSH and FT3 are useful predictors for DN in patients with T2DM.