What is the incidence of inadvertent hypothermia in elderly hip fracture patients and is this associated with increased readmissions and mortality?

Background: Globally the incidence of fragility hip fractures is rising with increasingly elderly and co-morbid patients. These injuries are associated with a high morbidity and mortality. Aims: This clinical study's primary outcome is to establish the rate of operative inadvertent hypothermia ( < 36 degrees C) in elderly hip fracture patients ( > 65 years old). We also aimed to identify risk factors and outcomes in patients with inadvertent hypothermia. Patients and Methods: A single centre, retrospective study of 929 hip fracture patients managed operatively between June 2015 and July 2017 was conducted. Patients' demographic, anaesthetic and surgical variables were analysed together with outcomes for length of stay (LoS), 30-day re-admissions, and 30-day mortality. Results: Overall rates of inadvertent hypothermia in elderly hip fracture patients undergoing surgery were 10%, with increasing age (p = 0.006) and pre-operative hypothermia (p < 0.0001) as risk factors. Patient's hypothermic pre-operatively compared with normothermic patients were 1.9 times more likely to be < 36 degrees C on leaving theatre. There was a trend towards a higher 30-day mortality (chi 2(1) = 2.818, p = 0.093), and a significantly higher mortality in patients undergoing SHS (p = 0.03). No survival differences for LoS were observed between hypothermic and >= 36 degrees C patients (chi 2(1) = 0.069, p = 0.79). 30-day re-admissions were higher in hypothermic patients (chi 2(1) = 16.301, p < 0.0001). Conclusion: Rates of inadvertent hypothermia are high in operatively managed hip fracture patients and are significantly associated with a higher 30-day readmission rate with a trend towards higher 30-day mortality.