Follow up of thyroid hormone parameters in chronically ill geriatric patients: screening for thyroid disorders at hospital admission justified.

The objective of this study was to investigate if screening of chronically ill geriatric patients for thyroid dysfunction is justified just upon hospital admission. TSH was measured in 124 patients at hospital admission and 11-86 (Median 37) days afterwards. FT4 was measured in cases with subnormal, suppressed or elevated TSH (43 cases). Out of 81 patients with normal (0.5-3.6 mU/l) TSH, the control value was subnormal (0.1-<0.5 mU/l) in 6 and elevated (>3.6 mU/l) in one case, but in none of the patients became suppressed (<0.1 mU/l). In 13/30 patients with subnormal TSH the control value was normal but in none of the patients suppressed or elevated. On the contrary, all cases with suppressed (N=9) or elevated (N=4) TSH remained in the same ranges at follow up. Low (<13 pmol/l, N=3) or elevated (>27 pmol/l, N=5) initial FT4 levels did not change in the follow up as well. Out of 35 patients with normal FT4, one became low and another elevated. Improvement or worsening of the clinical state in the follow up did not correlate to changes of TSH. The prevalence of unsuspected thyroid dysfunctions were 11.3% (hyperthyroidism clinical: 4, subclinical: 5, hypothyroidism clinical: 3, subclinical: 2 cases). All cases except one with subclinical hypothyroidism were detected by the initial screening. Only one patient with clinical hyperthyroidism was initial misinterpreted as having subclinical disease. Conclusions: In chronically ill geriatric patients investigated at hospital admission, a measurable TSH practically excludes hyperthyroidism in the follow up. Suppressed TSH levels remain suppressed but subnormal levels should be controlled because their normalization frequently occur in the follow up. Screening upon hospital admission is sensitive enough to detect cases of thyroid dysfunction and justified by their high prevalence.