Low prevalence of hypopituitarism after traumatic brain injury: a multicenter study

Objective: Hypopituitarism after traumatic brain injury (TBI) is considered to be a prevalent condition. However, prevalence rates differ considerably among reported studies, due to differences in definitions, endocrine assessments of hypopituitarism, and confounding factors, such as timing of evaluation and the severity of the trauma. Aim: To evaluate the prevalence of hypopituitarism in a large cohort of TBI patients after long-term follow-up using a standardized endocrine evaluation. Study design: Cross-sectional study. Patients and methods: We included 112 patients with TBI, hospitalized for at least 3 days and duration of follow-up>1 year after TBI from five (neurosurgical) referral centers. Evaluation of pituitary function included fasting morning hormone measurements and insulin tolerance test (n = 90) or, when contraindicated, ACTH stimulation and/or CRH stimulation tests and a GH releasing hormone-arginine test (n = 22). Clinical evaluation included quality of life questionnaires. Results: We studied 112 patients (75 males), with median age 48 years and mean body mass index (BMI) 26.7 +/- 4.8 kg/m(2). Mean duration of hospitalization was 11 (3-105), and 33% of the patients had a severe trauma (Glasgow Coma Scale < 9) after TBI. The mean duration of follow-up was 4 (1-12) years. Hypopituitarism was diagnosed in 5.4% (6/112) of patients: severe GH deficiency (n = 3), hypogonadism (n = 1), adrenal insufficiency (n = 2). Patients diagnosed with pituitary insufficiency had significantly higher BMI (P = 0.002). Conclusion: In this study, the prevalence of hypopituitarism during long-term follow-up after TBI was low. Prospective studies are urgently needed to find reliable predictive tools for the identification of patients with a significant pre-test likelihood for hypopituitarism after TBI.