Understanding mortality rates after hip fracture repair using ASA physical status in the National Hip Fracture Database

Abstract

Hip fracture is the most common reason for older patients to need emergency anaesthesia and surgery. Up to one-third of patients die in the year after hip fracture, but this view of outcome may encourage therapeutic nihilism in peri-operative decisions and discussions. We used a multicentre national dataset to examine relative and absolute mortality rates for patients presenting with hip fracture, stratified by ASA physical status. We analysed ASA physical status, dates of surgery, death and hospital discharge for 59,369 out of 64,864 patients in the 2015 National Hip Fracture Database; 3914 (6.6%) of whom died in hospital. Rates of death in hospital were 1.8% in ASA 1-2 patients compared with 16.5% in ASA 4 patients. Survival rates for ASA 4 patients on each of the first three postoperative days were: 98.8%, 99.1% and 99.1% (compared with figures of > 99.9% in ASA 1-2 patients over these days). Survival on postoperative day 6 was 99.4% for ASA 4 patients. Nearly half (48.6%) of the 1427 patients who did not have surgery died in hospital. Although technically sound, a focus on cumulative and relative risk of mortality may frame discussions in an unduly negative fashion, discouraging surgeons and anaesthetists from offering an operation, and deterring patients and their loved ones from agreeing to it. A more optimistic and pragmatic explanation that over 98% of ASA 4 patients survive both the day of surgery and the day after it, may be more appropriate.

Keywords: ASA physical status; hip fracture; mortality; older people; surgery.