The incidence of thyroid function abnormalities in patients attending an outpatient lipid clinic

Thyroid disorders are known to influence lipoprotein metabolism. In the cur rent study we examined the incidence of thyroid function abnormalities in p atients attending our outpatient lipid clinic. During the last 2 years, 248 patients were admitted to our lipid clinic for the diagnosis and managemen t of dyslipidemia. In all cases, a detailed medical history was obtained an d a thorough physical examination was performed with emphasis on the presen ce of symptoms/signs indicative of underlying thyroid diseases. In addition to lipid parameters, thyrotropin (TSH) and free thyroxine (FT4) levels wer e measured in a fasting blood sample. Seven female asymptomatic patients (2 .8%) had frank biochemical hypothyroidism, and 11 patients (9 female, 2 mal e) (4.4%) had subclinical hypothyroidism with TSH levels between 5.8-19 mU/ L. After restoration of a euthyroid state with levothyroxine therapy, no si gnificant changes in serum lipid parameters were observed in the whole grou p of patients with subclinical hypothyroidism. However, in 4 patients with TSH levels >12 mU/L relatively small doses of levothyroxine (75 mu g/day) w ere followed by a significant improvement of serum lipid profile. Interesti ngly, 3 patients exhibited clinical or subclinical hyperthyroidism that inf luenced serum lipid parameters as well as the effectiveness of hypolipidemi c treatment. It is concluded that thyroid function abnormalities are relati vely common in dyslipidemic patients attending a lipid clinic and could sig nificantly affect the patients' lipid profile as well as the patients' mana gement.