Association of Thyroid Status with Health-Related Quality of Life in Korean Older Adults

BACKGROUND: While hypothyroidism is associated with negative health effects in the general population, older adults with hypothyroidism have better physical function and comparable rates of depression and cognitive impairment relative to their euthyroid counterparts. The aim of this study was to investigate the association between thyroid status and health-related quality of life in Korean older adults. METHODS: In this population-based cross-sectional study, 1,060 adults aged over 60 years were classified by thyroid status into four groups based on their thyroid stimulating hormone (TSH) and free T4 values: overt hypothyroid, subclinical hypothyroid, euthyroid, and subclinical hyperthyroid. The main outcome measure was self-reported health-related quality of life based on the three-level version of the EuroQol-5 dimension (EQ-5D), with utility values of -0.171 and 1.000 corresponding to the worst and best health statuses, respectively. The adjusted means of the EQ-5D three-level version utility values according to thyroid status were determined using a linear regression analysis. RESULTS: In the adjusted analysis, the overt hypothyroid group showed significantly higher EQ-5D three-level version utility values than did the euthyroid group (0.998 vs. 0.908, P=0.000). In the subgroup analyses by sex, the overt hypothyroid group also showed significantly higher EQ-5D three-level version utility values for both men and women than did the euthyroid group (0.998 vs. 0.940, P=0.008; 0.983 vs. 0.882, P=0.001). CONCLUSION: Asymptomatic Korean older adults aged over 60 years with TSH and free T4 values corresponding to overt hypothyroidism have better health-related quality of life than their euthyroid counterparts.