Background
Hypothyroidism is closely related to dyslipidemia. There is still debate as to which patients need hormone replacement therapy (HRT) after hemithyroidectomy (HT), and little is known about the effect of HRT after HT. To address this, we aimed to investigate the effect of HRT in the incidence of dyslipidemia among three groups; TT with HRT (TT+HRT), HT with HRT (HT+HRT) or without HRT (HT-HRT).
Methods
This was a retrospective cohort study, and 3,057 patients who underwent thyroidectomy at Yeungnam university hospital in 2011-2014 were included. We excluded subjects diagnosed as dyslipidemia, hypothyroidism before surgery and taking lipid-lowering agents. Dyslipidemia was defined as triglyceride ≥200mg/dl, low-density-lipoprotein ≥160mg/dl, total-cholesterol ≥240mg/dl, or high-density-lipoprotein ≤40mg/dl. Thyroid-stimulating hormone (TSH) level and lipid profiles were assessed annually for 5 years.
Results
545 participants were finally enrolled and divided into 3 groups; TT+HRT (n=436), HT +HRT (n=37), and HT-HRT (n=72). The mean age was 52.96 and females were 87.9%. The occurence rate of dyslipidemia in TT+HRT and HT+HRT was 28.7% (hazard ratio [HR] = 1.389; 95% confidence interval [CI] = 0.825-2.339, p=0.216) and 45.9% (HR = 2.634, 95% CI = 1.329-5.221, p=0.006), as compared with 22.2% in HT-HRT (p-for-trend=0.015). The mean TSH level at the end of follow-up was not significantly different (p=0.410).
Conclusion
Even TSH level was not different between HT groups, HT+HRT group showed higher dyslipidemia incidence rate than HT-HRT group. These results suggest that surveillance for dyslipidemia may be necessary in patients with HT who need HRT.