Cortisol, Insulin, and Glucose and the Risk of Delirium in Older Adults with Hip Fracture

OBJECTIVES: To determine the relationship between perioperative delirium and cortisol, glucose, and insulin in older adults acutely admitted for hip fracture. DESIGN: Prospective cohort study. SETTING: Tertiary university center. PARTICIPANTS: Consecutive individuals aged 65 and older acutely admitted for hip fracture were invited to participate. MEASUREMENTS: All participants were repeatedly examined to determine presence and severity of delirium. Blood samples for cortisol, glucose, and insulin were drawn at 11: 00 a. m. Differences in characteristics of participants with and without delirium were evaluated using t-tests and Mann-Whitney tests. A logistic regression analysis was performed to correct for other important risk factors for delirium. RESULTS: One hundred forty-three participants, 70 (49%) with delirium and 73 (51%) without, were included. In univariate analyses, there was a trend toward higher cortisol levels (odds ratio = 1.003 (95% confidence interval = 1.001-1.004, P = .004), but this association was not statistically significant after multivariable analysis and may reflect an association between high cortisol and preexisting cognitive and functional impairment, and there was no association with insulin or glucose levels. Adjusting for sex and prefracture cognitive and functional impairment made the trend with cortisol and delirium statistically nonsignificant. CONCLUSION: Delirium in older adults acutely admitted for hip fracture may be linked with higher cortisol concentrations, but it may be that this association reflects an association between higher cortisol and preexisting cognitive and functional impairment. J Am Geriatr Soc 59: 1692-1696, 2011.