Concentrations of Thyroid Hormone Derivatives are Altered in Inpatients

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 449-497-Thyroid Neoplasia & Case Reports
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-462
Jacqueline Jonklaas1, Anpalakan Sathasivam*2, Hong Wang3, David Finigan4, Offie P Soldin1, Kenneth D Burman5 and Steven Soldin6
1Georgetown Univ Med Ctr, Washington, DC, 2Georgetown University Hospital, Bethesda, MD, 3Medstar Health Research Institute, 4Georgetown University, 5Washington Hospital Center, 6National Institutes of Health
Concentrations of 3-iodothyronamine reported in human serum are variable and method-specific. 3, 3-diiodothyronine concentrations generally parallel concentrations of other iodothyronines. Our objective was to conduct a pilot study examining the serum concentrations of 3-iodothyronamine and 3, 3-diiodothyronine in groups of inpatients and outpatients to see if their levels were affected by illness or other specific conditions.

One hundred patients (37 inpatients and 63 outpatients) consented to give a blood sample for the study. Physiologic data and medical conditions were documented. 3, 3-diiodothyronine and 3-iodothyronamine concentrations were measured by liquid chromatography tandem mass spectrometry.  

In univariate analyses decreased 3-iodothyronamine concentrations (0 vs > 0 pg/ml) were associated with a diagnosis of stroke (15% vs 0%, p value 0.023), hospitalization in the critical care unit (43% vs 16%, p value 0.008), and being an inpatient (47% vs 16%, p value 0.025). The following groups of 3, 3-diiodothyronine concentrations (2.01-7.48 vs 7.74-12.4 vs 12.5-17 vs 17.9-45.8 pg/ml) were associated with decreasing occurrence of critical illness (58% vs 11% vs 0% vs 8%,), stroke (29% vs 7.7% vs 4% vs 0%), being in a critical care unit (75% vs 39% vs 8.3 % vs 12%), and being an inpatient (83% vs 42% vs 8% vs 12%), p values for each of these 3 conditions being <0.0001. The same concentration groups were associated with increased occurrence of the athyreotic, levothyroxine replaced state in outpatients (4% vs 11% vs 17 % vs 60%). No other medical conditions such as hypertension or diabetes were associated.

In multivariate analyses, accounting for age and gender, inpatient status was associated with decreased concentrations of 3, 3-diiodothyronine (estimate -0.62, standard error 0.12, p value <0.0001), and 3-iodothyronamine (odds ratio 0.145, 95% CI 0.045-0.471). The athyreotic state remained associated with increased concentrations of 3, 3-diiodothyronine (estimate 0.26, SE 0.13, p value 0.04). No other specific conditions continued to be significant.

We confirm that sufficient 3, 3-diiodothyronine is made from peripheral conversion to maintain levels in patients dependent on levothyroxine. We also newly demonstrate associations between the inpatient status and reduced 3, 3-diiodothyronine and 3-iodothyronamine concentrations. The finding of an association between low 3-iodothyronamine concentrations and being an inpatient was unanticipated, given that prior studies suggest elevated levels in some pathologic conditions, These would appear to be global changes associated with illness in general, given that associations with specific medical conditions were not identified. Whether these are adaptive or maladaptive generalized changes associated with illness would need to be elucidated in an appropriately powered non-pilot study.

Nothing to Disclose: JJ, AS, HW, DF, OPS, KDB, SS

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Sources of Research Support: UL1TR000101