The efficacy of long term thyrostatic treatment in elderly patients with toxic nodular goitre compared to radioiodine therapy with different doses.

The objective of the study was to investigate the efficacy of long term thyrostatic versus radioiodine treatment of hyperthyroidism in old age. Our study is a retrospective analysis of the therapeutical outcome in 66 patients over 60 years of age with toxic nodular goitre. The patients were divided in two groups: Group A: 28 patients on methimazole treatment: starting dose 5-30, median (M) 10 mg, maintenance dose 2.5-15 (M = 5) mg, follow up 6 to 240 months (M = 23.5 months). Group B: 38 patients treated by either 100-300 MBq (N = 14, subgroup B1) or 325-1000 MBq (N = 24, subgroup B2) 131I, follow up: 18 to 156 months (M = 48 months). The efficacy of the different therapeutical approaches were compared by calculating the occurrence rate of persisting and relapsing thyroid dysfunctions and associated side effects. The 28 patients on methimazole treatment became euthyroid after 1-16 (M = 5) months but numerous relapses occurred in the follow up: hyperthyroidism, clinical: 5, subclinical 13, (relapse duration: M = 8 months; associated symptoms: hypertension in 4, cardiac arrhythmia in 3, cerebral embolism in 1, angina pectoris in 2, weight loss in 2 cases). Poor patient's compliance (9/28) or dose reduction by the physician (5/28) were the main causes of the relapses. Transient clinical (3 cases) or subclinical (6 cases) hypothyroidism also occurred (duration: 1-3 M = 2 months, no clinical symptoms). In 7 out of 14 (50%) patients receiving 100-300 MBq 131I (Group B1) hyperthyroidism persisted (versus 4/24 -16.7%- in Group B2 following 325-1000 MBq 131I; chi2(1) = 4.78 P = 0.028), methimazole treatment had to be continued in 9/14 patients (64.3%) (versus 5/24 -20.8%)- in Group B2., chi2(1) = 7.18 P = 0.0074) and in 5/14 (35.7%) the radiotherapy had to be repeated (versus 5/24 -020.8%- in Group B2, not sign.). Our conclusions are: 1) long term thyrostatic treatment is not safe in elderly patients with toxic nodular hyperthyroidism, mainly because of poor compliance or dose reduction by the physician; 2) radioiodine treatment as the first choice should be recommended for these patients and higher doses should be preferred.

Comparative screening for thyroid disorders in old age in areas of iodine deficiency, long-term iodine prophylaxis and abundant iodine intake.

OBJECTIVE: To investigate the effect of varying amounts of iodine intake on the prevalence of thyroid dysfunction, autoimmunity and goitre in old age. DESIGN: The first screening study where elderly subjects with varying amounts of iodine supply but from the same geographical and ethnographical region (Carpathian basin) were compared, and all hormone measurements and ultrasonography were performed by the same laboratory or person. PATIENTS: Nursing home residents were screened for thyroid disorders from: (A) an iodine-deficient area, Northern Hungary (n = 119; median age 81 years; median iodine excretion (MIE) 0.065 mumol/mmol creatinine (equivalent to 72 micrograms/g creatinine); (B) an area of obligatory iodinated salt prophylaxis since the 1950s, Slovakia (n = 135; median age 81 years, MIE 0.090 mumol/mmol creatinine (equivalent to 100 micrograms/g creatinine)) and (C) an abundant iodine intake area, Eastern Hungary (n = 92; median age 78 years; MIE 0.462 mumol/mmol creatinine (equivalent to 513 micrograms/g creatinine)). MEASUREMENTS: TSH, T4, free T4, T3, thyroglobulin (Tg), antibodies to Tg (AbTg) and to thyroid peroxidase (AbTPO), iodine excretion, ultrasonography of the thyroid gland. RESULTS: In regions A, B, and C, the prevalence of unsuspected clinical hypothyroidism was 0.8%, 1.5% and 7.6% (P = 0.006), with all cases except one being antibody positive (Ab+). The occurrence of subclinical hypothyroidism was 4.2% in region A, 10.4% in region B and 23.9% in region C (P < 0.001), but only 3 of 22 cases with subclinical hypothyroidism from region C were Ab+. The overall prevalence of Ab positivity (either antiTg+ or antiTPO+) was similar in the three regions (A, 19.3%; B, 24.4%; C, 22.8%). The occurrence of hyperthyroidism (clinical plus subclinical) was 3.4% in region A, 3.0% in region B and 0% in region C (not significant). The rate of elevated Tg levels was similar in the three regions. The prevalence of goitre was 39.4%, 16.4% and 12.2% (P < 0.001), respectively in regions A, B and C. In euthyroid subjects the mean ultrasonographically determined thyroid volume was 21.9 ml in region A, 13.6 ml in region B and 15.1 ml in region C (ANOVA F = 5.76; P = 0.0038). There was no significant difference in the occurrence of cases with hypoechogenic echotexture of the thyroid gland. CONCLUSIONS: The screening for hypothyroidism in nursing home residents living in iodine-rich regions is justified by the high prevalence of unsuspected clinical hypothyroidism. The high prevalence of antibody positivity in old age is independent of the iodine supply, but iodine supply has a determining role in the development of autoimmune hypothyroidism in the aged. Most cases of subclinical hypothyroidism in iodine-rich regions are not of autoimmune origin. In old age, hypoechogenic texture of the thyroid gland is not predictive of thyroid dysfunction.