FACTORS AFFECTING THYROID-FUNCTION AFTER THYROIDECTOMY FOR GRAVES-DISEASE

A series of 108 patients with surgically treated Graves' disease were analyzed retrospectively in an attempt to determine factors that could affect postoperative thyroid function. Univariate analysis showed tha t remnant size, resected thyroid weight, antithyroid microsomal antibo dy and antithyroglobulin antibody titers were all significantly relate d to the postoperative outcome. Remnant size outweighed the other fact ors in prediction of thyroid status following subtotal thyroidectomy. When all the potential prognostic factors were individually adjusted b y remnant size, only the degree of lymphocytic infiltration and antith yroid microsomal antibody titer were significantly associated with the postoperative outcome. Within the range of optimal remnant size, the higher the antithyroid microsomal antibody titer and the degree of lym phocytic infiltration, the greater the likelihood of postoperative hyp othyroidism and the lower the chance of recurrence. Further stepwise d iscriminant analysis revealed that remnant size can be planned accordi ng to the known preoperative antithyroid microsomal antibody titer to achieve the greatest likelihood of a postoperative euthyroid state. Th e model suggested that when the antibody titer is less than or equal t o 640, the remnant size should be 3 to 5 cm(3); if the antibody titer is 1,280 to 2,560, then the remnant size should be 4 to 5 cm(3); and i f the antibody titer is (l)ess than or equal to 5,120, then the remnan t size should be around 5 cm(3).