Predictive value of circulating insulin-like growth factor I levels in ischemic stroke outcome

Context: Cerebrovascular disease is highly prevalent in the general population, frequently leading to permanent invalidity and reduced quality of life. IGF-I is recognized as an important neuroprotective factor against cerebral hypoxic insult. Objective: The objective of the study was to evaluate pituitary function, in particular GH-IGF-I axis, in adult patients receiving rehabilitation after an ischemic stroke. Subjects and Methods: We studied 42 patients ( 12 females; age range, 50 - 88 yr) during rehabilitation after stroke, evaluating the relationship between the GH-IGF-I axis and the severity ( National Institutes of Health stroke scale) and outcome [Rancho Los Amigos Scale of Cognitive Functioning (LCFS); Functional Independence Measure (FIM); modified Ranking Scale] from stroke. Results: GH deficiency was demonstrated in five patients (11.9%). Peak GH after GHRH + arginine test and IGF-I levels did not correlate with severity of stroke. IGF-I was positively correlated with LCFS (r = 0.305, P < 0.05) and the difference between FIM on admission and at discharge from rehabilitation (Delta FIM; r = 0.361, P < 0.02). Outcome indexes ( LCFS, FIM at discharge, Delta FIM) and occurrence of favorable outcome ( modified Ranking Scale 0 - 1) were significantly (P < 0.05) higher in patients with IGF-I levels 161.8 mu g/dl or greater (50th percentile of the patient distribution). LH-FSH deficiency (three cases), ACTH deficiency ( one case), and hyperprolactinemia (two cases) were detected. One patient had primary hypogonadism, and six males had low testosterone with normal LH and FSH levels. By multivariate analysis, IGF-I level was the main significant predictor of Delta FIM and LCFS. Conclusions: Ischemic stroke may be associated with pituitary dysfunction, particularly GH and gonadotropin deficiencies. The higher IGF-I levels observed in patients with better outcome suggest a possible neuroprotective role of IGF-I. Circulating IGF-I may predict functional performance during rehabilitation and ischemic stroke outcome.