Hypothermia and low body temperature are common and associated with high mortality in hip fracture patients

Hip fractures remain one of the commonest injuries treated by orthopaedic surgeons. Despite recent initiatives, the fracture engenders a very high mortality. The UK National Hip Fracture Database reports a 30-day mortality of 8%. The pathophysiology that results in such high mortality remains imperfectly understood. The significance of thermal dysregulation in polytrauma is becoming increasingly recognised. Hypothermia is a common feature of polytrauma and is associated with adverse outcomes. No previous studies have explored the prevalence and outcomes of hip fracture patients with hypothermia and/or low body temperature. We sought to evaluate this. We prospectively collected the demographic details and admission tympanic temperature of all patients presenting to our institution with hip fracture. Patient mortality was also recorded. Seven hundred and eighty-one patients were included. The mean age was 80 years. 38% (300) had a temperature below 36.5°C. 4% (30) presented with a tympanic temperature greater than 37.5°C. The 30-day mortality for patients with a normal admission temperature (between 36.5° and 37.5°C) was 5.1%. This value was 15.3% for those whose admission temperature was less than 36.5°C (p<0.0001). Correcting for potential confounders of age and gender, those with an admission temperature of less than 36.5°C had a 2.8 fold increase in the odds of mortality at 30-days compared with those with an admission temperature of between 36.5° and 37.5°C (p<0.0005). Low body temperature is strongly linked to 30-day mortality in hip fracture patients.