Prevalence of Thyroid Disease and Abnormal Thyroid Tests in Older Hospitalized and Ambulatory Persons

To determine the utility of laboratory tests for diagnosing thyroid disease in the hospitalized elderly, we measured serum thyroid‐stimulating hormone (TSH), thyroxine (T 4 ), free thyroxine index (FT 4 I), triiodothyronine (T 3 ), and free triiodothyronine index (FT 3 I) in 125 geriatric inpatients, mostly men, and compared the results to those in elderly ambulatory patients. Hypothyroidism (TSH > 10 μU/mL with a low T 4 and FT 4 I or clinical findings) was present in 7.8% (nine of 116) of male inpatients compared to only 0.7% of male ambulatory controls (P < 0.01). Only a few women were studied but 17% (two of 12) were hypothyroid compared to 2.4% of ambulatory elderly women. Three of the hypothyroid inpatients had no clinical clue to their hypothyroidism. Further, decreased thyroid reserve or subclinical hypothyroidism (TSH > 10 μU/mL with a normal T 4 and FT 4 I and no overt clinical findings), a condition which may lead to overt hypothyroidism, was more common in male inpatients (4.3%) than in male ambulatory controls (1.8% [ P < 0.01]). Thus, a clearly elevated serum TSH (> 10 μU/mL) was more common in inpatient (12.1%) than in ambulatory (2.4%) elderly men ( P < 0.01). Four inpatients and nine ambulatory controls had an elevated T 4 and FT 4 I, but in only one (0.8%) inpatient and one (0.6%) control was a final diagnosis of hyperthyroidism made; the others had no clinical findings and a normal or low T 3 and FT 3 I. A low T 3 and FT 3 I or T 4 and FT 4 I occurred with equal prevalence in inpatient (19%) as in ambulatory older men (14.9%); three of 12 women inpatients also had a low T 3 and FT 3 I. This finding did not aid in diagnosing thyroid dysfunction. Because of the high prevalence of thyroid disease, predominantly hypothyroidism, in the inpatients (9.4%, or 14.1% if decreased thyroid reserve is included) and the difficulty in detecting thyroid disease on clinical grounds (27% of inpatients with thyroid disease had no specific clinical manifestation), we recommend that geriatric patients, including men, be screened for thyroid dysfunction by measurements of serum TSH and T 4 (or FT 4 I) upon hospital admission.