Impact of Growth Hormone Deficiency on Quality of Life in Traumatic Brain Injury Adults

Growth hormone deficiency (GHD) is the most common chronic hormone deficit following traumatic brain injury (TBI) with variable prevalence (average of 10-15%), likely a reflection of the timing and methods of testing, age, and injury severity. Previous guidelines recommend assessment of GHD with serum IGF-1. However, studies have found IGF-1 lacks specificity and sensitivity and does not correlate with dynamic testing in patients with mild TBI and GHD. The primary objective of this observational study is to determine whether the Quality of Life in Adult Growth Hormone Deficiency Assessment (QoL-AGHDA) can aid in predicting GHD in patients with mild TBI. Patients aged 18-75 years with a diagnosis of mild TBI (American congress of rehabilitation 2023 guidelines and Centre for disease control and prevention definition of traumatic brain injury) with persistent symptoms at 1-year post-injury attending the Calgary Brain Injury program and the chronic pain centre will be screened for suspected GHD by physicians. Eligible participants will complete the QoL-AGHDA along with other symptom based measures and will be referred to endocrinology for provocative testing for GHD (glucagon stimulation testing). The secondary objective is to determine if the QoL-AGHDA can provide an objective measure of growth hormone treatment efficacy in patients with TBI and GHD. To address this, participants found to have GHD (peak GH of <3mcg/L following glucagon stimulation test) will be provided with growth hormone replacement (Genotropin, Pfizer) for 3 months. Participants will be asked to repeat questionnaires (QoL-AGHDA and additional symptom measures) bi-weekly throughout the 3-months of treatment. Exploratory sleep assessment: 1. Participants will be invited to participate in one or both optional sleep components of the study. All participants will be offered 6 consecutive days and nights of wrist actigraphy (MotionWatch8, CamNtech) following completion of the glucagon stimulation test or initial endocrinology appointment. The wrist-worn accelerometer will objectively measure sleep patterns, duration, and rest-activity cycles, while participants will complete a brief daily electronic sleep diary to capture subjective sleep characteristics. Participants diagnosed with GHD will be invited to repeat the actigraphy protocol and sleep diary after 3 months of growth hormone replacement therapy. 2. A subset of approximately 30 participants will also complete two consecutive nights of at-home polysomnography (PSG) using the Nox SAS Solution (Nox Medical, Reykjavik, Iceland). Participants will receive written and video instructions for self-application of the device. The second night of PSG will be used for analysis to characterize objective sleep architecture and identify sleep disturbances using physiological measures including brain activity, respiratory parameters, oxygen saturation, heart rate, body position, and movement. The PSG subgroup will include approximately 10 healthy controls, 10 participants with persistent symptoms following mild TBI without GHD, and 10 participants with persistent symptoms following mild TBI and GHD. Healthy controls will complete baseline demographic and medical history forms, medication use questionnaires, and the Epworth Sleepiness Scale prior to PSG.