Relation of thyroid disfunction, thyroid autoantibodies, and renal function

Fifty-eight patients with thyroid dysfunction were included, comparing 27 healthy subjects to evaluate the relationship between thyroid autoimmunity, thyroid functional status, and renal function. Regardless of clinical status, hypothyroidism was defined as T3 - T4 < normal limits and TSH > upper limit of normal, and hyperthyroidism was defined as T3 - T4 > normal limits and TSH < 0.1 mcU/mL. In all participants, serum antithyroperoxidase level, serum antithyroglobulin level, creatinine clearance ( CC), and urinary albumin excretion rate ( UAER) in 24-h urine collections were measured. Of 85 persons, 41 patients ages 20 to 71 years ( median; 44) had hypothyroidism, 17 patients ages 22 to 56 years ( median; 32) had hyperthyroidism, and 27 subjects ages 20 to 67 years ( median; 50) were normal. Regarding thyroid autoantibody positiveness, the positive group had a higher UAER than the negative group (30.2 mg/day, 20.8 mg/day, respectively; p = 0.05). In hypothyroid patients, UAER was significantly higher than in hyperthyroid patients and control subjects (30.1 mg/day, 11.8 mg/day, 10.5 mg/day, respectively; p < 0.001). In the hypothyroid population, with regard to UAER and CC, we could not find a significant difference between the thyroid autoantibody positive and negative groups. In view of CC, hypothyroid patients had significantly lower CC than the hyperthyroid group (79.0 mL/ min, 86.5 mL/ min, respectively; p < 0.01). A careful control of the renal function in thyroid diseases should be evaluated. Renal dysfunction seems to be secondary to hypothyroidism rather than thyroid autoimmunity.