Postoperative delirium and pre-fracture disability predict 6-month mortality among the oldest old hip fracture patients.

Background: Age is one of the most robust risk factors for hip fracture. Recent projections indicate that almost half of hip fractures are occurring with an increasing trend among the "oldest old" (i.e., in those aged >85 years).

Aims: To compare clinical characteristics, outcomes, and risk factors for 6-month mortality in two groups of "oldest old" patients (group 1 = 85-89, group 2 > 90 years), after hip fracture surgery.

Methods: Observational prospective cohort study with 6-month follow-up, performed in an Orthogeriatric Unit of an academic hospital between March 2007 and November 2012.

Results: Two hundred seventy-five patients (group 1: N = 171; group 2: N = 104) underwent a comprehensive geriatric assessment, including demographics, clinical, functional, nutritional, and mental status. The 6-month rehospitalization and mortality rates after surgery were assessed through structured telephone interviews with patient's caregivers. Multivariate logistic regression models were used to evaluate predictors of 6-month mortality, adjusting for relevant covariates. Fifty-eight patients died at follow-up. The in-hospital and 6-month mortality rates were significantly higher for patients of group 2 than for those of group 1. After adjusting for covariates, the multivariate logistic regressions showed that severe disability (OR 2.24, 95 % CI 1.08-4.65) and postoperative delirium (POD) (OR 3.80, 95 % CI 1.72-8.39) were predictors of 6-month mortality.

Conclusions: Patients aged >90 years who underwent hip fracture surgery are more likely to die at 6 months than those aged 85-89 years. Pre-fracture disability and POD are predictors of this excess of mortality.