THYROID HORMONE REPLACEMENT REDUCES THE RISK OF CARDIOVASCULAR DISEASES IN DIABETIC NEPHROPATHY PATIENTS WITH SUBCLINICAL HYPOTHYROIDISM

Abstract

OBJECTIVE: Patients with diabetic nephropathy (DMN) have an increased risk of cardiovascular disease (CVD). However, strategies to reduce this risk are limited. Thyroid hormone replacement therapy (THRT) in patients with hypothyroidism has been shown to reduce several surrogate markers of CVD. Therefore, we performed a study to determine if THRT would reduce CVD risk in patients with subclinical hypothyroidism (SCH) and DMN. METHODS: This was a retrospective, nonrandomized study of patients with type 2 diabetes, DMN, and SCH. Those with known thyroid dysfunction or taking THRT at baseline were excluded. Patients receiving THRT for at least 180 days were included in the THRT group, while the remaining patients were assigned to the non-THRT group. The primary outcome was CVD events, which included coronary syndrome, cerebrovascular events, and peripheral artery diseases. RESULTS: Among the 257 patients, 83 (32.3%) were in the THRT group. The mean ages were 62.7 +/- 12.3 and 66.8 +/- 12.4 years in the THRT and non-THRT groups, respectively. The corresponding numbers of male patients were 32 (40.0%) and 94 (53.1%). During a mean follow-up of 38.0 +/- 29.2 months, 98 CVD events were observed. Acute coronary syndrome and cerebrovascular event prevalence rates were lower in the THRT group than the non-THRT group, but there was no difference for peripheral artery diseases. Multivariate Cox analysis revealed that THRT was independently associated with a decreased CVD event risk. CONCLUSION: THRT may decrease the risk of CVD in DMN patients with SCH. Randomized trials are needed to verify this finding. ABBREVIATIONS: CV = cardiovascular DMN = diabetic nephropathy eGFR = estimated glomerular filtration rate fT4 = free thyroxine HbA1c = glycosylated hemoglobin HR = hazard ratio hs-CRP = high-sensitivity C-reactive protein LDL-C = low-density lipoprotein cholesterol SCH = subclinical hypothyroidism T2DM = type 2 diabetes THRT = thyroid hormone replacement therapy TSH = thyroid-stimulating hormone.