Prevalence of hypopituitary test results in patients with traumatic brain injury – results from The Danish National study on posttraumatic hypopituitarism

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 130-162-Neuroendocrinology
Clinical
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-146
Marianne Klose*1, Marianne Andersen2, Jurgita Janukonyté3, Louise Frederiksen2, Kirstine Stochholm3, Peter Laurberg4 and Ulla Feldt-Rasmussen1
1Copenhagen University Hospital, Rigshospitalet, 2Odense University Hospital, Denmark, 3Aarhus University Hospital, Denmark, 4Aalborg Hospital, Aalborg, Denmark
Introduction:Traumatic brain injury (TBI) has been acknowledged as a frequent cause of hypopituitarism. The finding of primarily isolated deficiencies and particularly isolated GH deficiency has emphasized a potential methodological confounding, including test-retest reproducibility, and appropriateness of cut-offs.

Aim:  We questioned the justification of general recommendations for assessment of hypopituitarism in patients with TBI, and aimed to describe the prevalence of hypopituitarism in a national TBI population of patients admitted to a Danish hospital in 2008, as compared to healthy controls.

Patients and Methods: We included 463 patients (18-65 years) hospitalized ≥ 24h, with more than subtle TBI as indicated by loss of consciousness, amnesia, or cranial/cerebral imaging abnormalities. The patients underwent endocrine assessment median 2.5 years (range 1.0 - 4.4) postTBI. Assessment included baseline evaluation of thyroid and gonadal hormone concentrations, and dynamic assessment of the GH and HPA axis. Results were compared to those from healthy controls. Deficiencies were defined according to local assay and test specific cut-offs.

Results: An insufficient 30 min. cortisol response to Synacthen® stimulation was more frequently seen in patients 26/344 (7.1%) than controls 0/113 (0%)(p=0.01), whereas an insufficient response to ITT was seen equally frequent in patients 9/204 (4.6%) and controls 3/116 (2.6%)(p=0.7). An insufficient GH response to PD-GHRH or GHRH-arginine was seen more often in patients 47/360 (11.6%) than controls 2/93 (2.1%)(p<0.01), whereas an insufficient peak GH to ITT was equally frequent in patients 9/200 (4.5%) and controls 2/88 (2.3%)(p=0.4). A total testosterone below the lower cut-off was seen in 32/300 (10.7%) male patients vs. 0/62 (0%) controls (p=0.01). In women, hypogonadism could not be excluded in 4/152 (2.6%) patients vs. 1/32 (3.1%) controls (p=0.9). Low free T4 was seen in 5/461 (1.1%) patients vs. 3/96 (3.1%) controls (p=0.1).

Conclusion: These preliminary results from the nationwide study of TBI patients assessed 2.5 years after the injury illustrates that the methodological approach for assessment of pituitary function is of importance when defining the prevalence of pituitary insufficiency. Hormonal responses of the various pituitary axes in TBI patients may or may not differ from what should be expected from healthy controls, and insufficiency should thus be confirmed by re-testing.

Disclosure: UF: Investigator, Novo Nordisk, Speaker, Novo Nordisk, Advisory Group Member, Pfizer Global R&D. Nothing to Disclose: MK, MA, JJ, LF, KS, PL

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: Copenhagen University, The Danish Agency for Science, Technology and Innovation, The Reseach Council of the Capital Region of Denmark, The Lundbeck Foundation, Novo Nordisk, The A.P. Moller Foundation for the Advancement of Medical Science, Arvid Nilssons Foundation, Christenson-Cesons Foundation, Axel-Muusfeldts Foundation and Else and Mogens Wedell-Wedellsborgs Foundation