Predictive value of early decreased plasma ghrelin level for three-month cognitive deterioration in patients with mild traumatic brain injury

• Ghrelin levels and relationship with cognitive deterioration after mild traumatic brain injury (mTBI) were tested.
• Ghrelin levels were lower in patients with cognitive deterioration than patients without cognitive deterioration.
• Decreased ghrelin level was identified as an independent predictor for three-months cognitive deterioration.
• Ghrelin level was negatively associated with serum adrenocorticotrophin hormone level and age.
• A ghrelin level of 41.6 pg/mL predicted cognitive deterioration with the optimal sensitivity and specificity values.

The orexigenic hormone, ghrelin, is tightly linked to cognition impairment in neurodegenerative disorders. No previous studies have investigated the early ghrelin concentration change in patients with mild traumatic brain injury (mTBI) and it's relationship to cognitive deterioration. This study was performed to investigate the early plasma ghrelin concentrations in patients with mTBI and to explore the relationship between ghrelin and cognitive deterioration. Plasma ghrelin concentrations of 118 adults after acute mTBI were determined by enzyme-linked immunosorbent assay. Forty patients (33.9%) had cognitive deterioration three months after mTBI. Plasma ghrelin levels were significantly lower in mTBI patients with cognitive deterioration than patients without cognitive deterioration (38.8 ± 4.5 pg/mL vs 50.8 ± 7.7 pg/mL, P < 0.001). Decreased Plasma ghrelin level was identified as an independent predictor for three-month cognitive deterioration after mTBI (odds ratio, 0.746; 95% confidence interval, 0.651–0.856; P < 0.001). Plasma ghrelin level was negatively associated with serum adrenocorticotrophin hormone level (t = −6.854, P < 0.001) and age (t = −6.112, P < 0.001). A plasma ghrelin level of 41.6 pg/mL predicted three-month cognitive deterioration after mTBI with the optimal sensitivity (85.9%) and specificity (80.0%) values (area under curve, 0.904; 95% confidence interval, 0.852–0.957; P < 0.001). The predictive value of ghrelin was bigger than that of serum adrenocorticotrophin hormone level (area under curve, 0.638; 95% confidence interval, 0.536–0.741; P = 0.014) and age (area under curve, 0.638; 95% confidence interval, 0.536–0.741; P = 0.014) for three-month cognitive deterioration after mTBI.