Decrease in Insulin-Like Growth Factor-1 and Insulin-Like Growth Factor-1 Ratio in the First Week of Stroke Is Related to Positive Outcomes.

Background: High insulin-like growth factor-1 (IGF-1), measured once during acute stroke, is associated with greater survival rates and lower stroke severity. However, information is lacking regarding how IGF-1 availability, determined by IGF-1's ratio to insulin-like growth factor binding protein-3 (IGFBP-3), relates to recovery and how the response of IGF-1 during the first week of stroke relates to outcomes. The purpose of this study was to determine the following: (1) the relationship between percent change in IGF-1 and IGF-1 ratio during the first week of stroke and stroke outcomes; and (2) the difference in percent change in IGF-1 and IGF-1 ratio in individuals being discharged home and individuals being discharged to inpatient facilities.

Methods: IGF-1 and IGFBP-3 were quantified from blood sampled twice (<72 hours of admission; 1 week post stroke) in 15 individuals with acute stroke. Length of stay, modified Rankin Scale at 1 month, and discharge destination were obtained from electronic medical records.

Results: Percent change in IGF-1 ratio was related to length of stay (r = .54; P = .04). Modified Rankin Scale (n = 10) was related to percent change in IGF-1 (r = .90; P < .001) and IGF-1 ratio (r = .75 P = .01). Individuals who went home (n = 7) had decreases in IGF-1 (-24 + 25%) and IGF-1 ratio (-36 + 50%), whereas individuals who went to inpatient facilities (n = 8) had increases in IGF-1 (37 + 46%) and IGF-1 ratio (30 + 40%). These differences were significant (IGF-1: P = .008; IGF-1 ratio: P = .01).

Conclusion: Our findings suggest that a decrease in IGF-1 and IGF-1 ratio during the first week of stroke is associated with favorable outcomes: shorter length of stay, greater independence at 1 month on the modified Rankin Scale, and discharging home.