Prevalence of hypothyroidism in a southeastern nursing home

BACKGROUND: It is common to find older patients who have received thyroid hormone replacement for years without clear-cut documentation of hypothyroidism. The diagnosis of hypothyroidism in older patients presents a difficult problem. OBJECTIVE: We sought to determine the prevalence of hypothyroidism and the sensitivity of clinical determinants for hypothyroidism during withdrawal of thyroid hormone therapy (vital signs, weight, MMSE, and depression scale) in a nursing home population. METHODS: We studied a cohort of patients in two nursing centers in southeast Georgia. Those receiving thyroid hormone without documented hypothyroidism had complete a physical examination and serum TSH, MMSE,depression scale assessment at baseline and 3 and 6 weeks after discontinuation of thyroid therapy. Weights and vital signs were monitored throughout the study. The hypothyroid state was defined by an attending physician by clear documentation of elevated TSH > 10 microIU/mL and clinical manifestation of hypothyroidism. RESULTS: Thirteen of 129 patients were receiving thyroid supplement; seven had documented hypothyroidism. Five of the six without documented hypothyroidism completed the study. Three of those five were found to be hypothyroid (TSH: 69.4-110.4 microIU/mL at 6 weeks of thyroid therapy). Among the clinical determinants, only weight correlated with elevated TSH and hypothyroidal state. At 6 weeks, the other two patients had borderline elevation of TSH, and one patient normalized at 4 months. Both had negative antimicrosomal antibodies and were considered euthyroid. CONCLUSIONS: The prevalence of true hypothyroidism ranged from 6.2% to 7.8%. We identified unnecessary therapy in two of 13 patients. Increased weight was the most sensitive indicator of evolving hypothyroidism.