Postoperative deliriun and pre-fracture disability predict 6-month mortality among the oldest old orthogeriatric patients

Background.– Advanced age is one of the most robust risk factors for hip fracture (HF). Recent projections showed that almost half of the HF will occur among the oldest old, i.e. those aged 85 years and older, with an increasing trend. Objectives.– To compare baseline characteristics, clinical outcomes and risk factors for 6-month mortality in two populations of patients, one aged 85-89 years (group 1) and the second 90 years or above (group 2), discharged after hip fracture surgery. Design. Observational prospective cohort study with follow-up at 6 months. Setting. Acute Orthogeriatric Unit (OGU) at San Gerardo University Hospital, Monza, Italy. Participants. 275 patients (group 1, n = 171; group 2, n = 104) consecutively admitted in the period March 2007–November 2012. Methods.– All patients underwent a comprehensive geriatric assessment including demographic characteristics, functional, nutritional and mental status, laboratory indices, variables related to the fracture and the surgical intervention, postoperative complications. We assessed mortality and rehospitalisation rates six months after discharge. Results.– Group 2 patients were significantly more dependent in activities of daily living (ADL) and cognitively impaired, and were less likely to be on oral anticoagulant therapy than those in group 1. The 6-month rehospitalisation rates were similar among groups, but the in-hospital and 6-month mortality rates were significantly higher in group 2 than group 1. Performing multivariate logistic regression models, we found that severe disability and postoperative delirium were the only independent predictors of 6-month mortality. The mortality risk (adjusted Odds Ratio) increased from four-fold to six-fold considering disability, and from 2.5 to 3.4 for delirium, according to the model. Conclusion.– Pre-fracture disability and postoperative delirium are the main predictors of 6-month mortality in the oldest old. Since delirium is a preventable condition, the efforts of physicians and nurses working in OGU should be addressed towards the prevention and the careful management of this syndrome.