Prevalence of hypothyroidism in a southeastern nursing home

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.

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.

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.

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.

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.