Pattern of recovery of thyroid hormone indices associated with treatment of diabetes mellitus.

The effects of diabetes mellitus on serum thyroid hormone parameters were studied in 54 patients divided into 4 groups. Treated asymptomatic patients (group I) had normal thyroid values which did not correlate with serum or urinary glucose. Untreated nonketoacidotic patients (group II) showed a mild persistent depression in T3 and an elevation in rT3. Patients with ketoacidosis with a brief history of symptoms (group III) had a moderate T3 decrease and a mild rT3 elevation which quickly resolved with treatment. Ketoacidotic patients with a long history of symptoms (group IV) had marked depression of T3 and elevation of rT3 which was only partially rectified by treatment. Serum T4 was generally normal, except for a minimal decrease on the day after admission, probably resulting from rehydration and a subsequent increase associated with an increase in TSH. We concluded that thyroid hormone parameters were not influenced by variations in serum glucose, but seemed to reflect the effects of a preexisting catabolic state, ketoacidosis, or both.