Trauma severity, but not hypopituitarism, affects cognitive function after traumatic brain injury: a multi-center study in The Netherlands
Nieke Kokshoorn1, Jan Smit1, Willy-Anne Nieuwlaat3, Nienke Biermasz1, Peter Bisschop2, Ronald Groote Veldman4, Ferdinand Roelfsema1, Anton Franken5, Moniek Wassenaar1, Jitske Tiemensma1, Johannes Romijn1 & Alberto Pereira1
Background: Hypopituitarism after traumatic brain injury (TBI) is considered to be a prevalent condition, and may affect quality of life (QoL) and cognitive function. However, the prevalence of hypopituitarism differs considerably among reported studies due to differences in definitions, endocrine assessments of hypopituitarism, and confounding factors, like timing of evaluation and the severity of the trauma.
Aim: To evaluate the prevalence of hypopituitarism, QoL, and cognitive function in a large cohort of TBI patients after long term follow-up.
Patients and methods: Ninety-one patients (62M, median age 46 years) with follow-up duration after TBI >1 year and hospitalized for a minimum of 4 days were recruited from 5 centers in The Netherlands. Pituitary function was evaluated by fasting morning samples combined with insulin tolerance test (ITT, n=77) or, when contraindicated, by ACTH and GHRHarginine test (n=14). QoL was assessed by 4 health related questionnaires (HADS, NHP, MFI-20, and SF-36); cognitive function by the Minimal Mental State Examination (MMSE) for global cognitive functioning; Verbal Learning Test of Rey (VLTR) and Rey Complex Figure test (RCF) for memory; and Trail Making Test (TMT), Stroop Color-Word test (SCWT) and Letter Digit Substitution test (LDST) for executive functioning.
Results: Hypopituitarism was present in 6.6% (6/91) of cases (severe GHD 4.4% (n=4), hypogonadism 1.1% (n=1); hypocortisolism 2.2% (n=2)). Hypopituitarism affected QoL (several items in all questionnaires), but not cognitive function. However, trauma severity (moderate/severe versus mild injury) affected cognitive function: memory: VLTR: immediate and delayed repeats: P=0.032, and 0.025, respectively) and executive functioning: SCWT: total interference P=0.021, and LDST: correct answers P=0.047.
Conclusion: The prevalence of hypopituitarism after TBI was low after long-term follow-up. QoL was affected by hypopituitarism, but not by the severity of the trauma. In addition, trauma severity, but not hypopituitarism, significantly affected cognitive function.