Session: SUN 414-431-HPT Axis Biology
Poster Board SUN-426
Objectives: To examine the risk of cardiovascular and all-cause mortality in relation to subclinical hyperthyroidism.
Methods: Patients consulting their general practitioner from 2000–2009 in Copenhagen, Denmark, who underwent thyroid blood tests, were identified by individual-level linkage of nationwide registries. Patients with a history of thyroid disease or related medication were excluded. Risk of cardiovascular mortality was analyzed using Kaplan-Meier curves and Poisson regression models were applied to estimate Incidence Rate Ratios (IRR).
Results: Of 574,595 included individuals (mean age 48.7 years [SD ±18.3]; 39.1% males) 550,927 (95.9%) were euthyroid, 1,603 (0.3%) had overt hypothyroidism, 11,834 (2.1%) subclinical hypothyroidism, 3,967 (0.7%) overt hyperthyroidism and 6,264 (1.1%) subclinical hyperthyroidism. Increased risk of cardiovascular mortality was found in two levels of subclinical hyperthyroidism (TSH <0.1, 0.1–0.2 mU/L and normal free thyroixine): IRR 1.24 [95% CI: 1.09–1.41], IRR 1.21 [1.09–1.34] and in “high-normal” levels of euthyroidism (TSH 0.2–0.4 mU/L): IRR 1.21 [1.13–1.29].
Conclusions: Subclinical hyperthyroidism and “high-normal” thyroid function are significant risk-factors for cardiovascular and all-cause mortality.