The risk of cardiorespiratory deaths persists beyond 30 days after proximal femoral fracture surgery

Abstract

Introduction

30-day mortality is routinely used to assess proximal femoral fracture care, though patients might remain at risk for poor outcome for longer. This work has examined the survivorship out to one year of a consecutive series of patients admitted for proximal femoral fracture to a single institution. We wished to quantify the temporal impact of fracture upon mortality, and also the influence of patient age, gender, surgical delay and length of stay on mortality from both cardiorespiratory and non-cardiorespiratory causes.

Patients and methods

Data were analysed for 561 consecutive patients with 565 fragility type proximal femoral fractures treated surgically at our trauma unit. Dates and causes of death were obtained from death certificates and also linked to data from the Office of National Statistics. Mortality rates and causes were collated for two time periods: day 0–30, and day 31–365.

Results

Cumulative incidence analysis showed that mortality due to cardiorespiratory causes (pneumonia, myocardial infarction, cardiac failure) rose steeply to around 100 days after surgery and then flattened reaching approximately 12% by 1 year. Mortality from non-cardiorespiratory causes (kidney failure, stroke, sepsis etc.) was more progressive, but with a rate half of that of cardiorespiratory causes. Progressive modelling of mortality risks revealed that cardiorespiratory deaths were associated with advancing age and male gender (p < 0.001 for both), but the effect of age declined after 100 days. Non-cardiorespiratory deaths were not time-dependent.

Conclusion

We believe this analysis extends our understanding of the temporal impact of proximal femoral fracture and its surgical management upon outcome beyond the previously accepted standard (30 days) and supports the use of a new, more relevant timescale for this high risk group of patients. It also highlights the need for planning and continuing physiotherapy, respiratory exercises and other chest-protective measures from 31 to 100 days.

Introduction

Despite widespread implementation of national guidelines [1], [2], improvements in care pathways and advances in surgical techniques, mortality after proximal femoral fractures remains high with rates of between 20% and 30% frequently quoted out to the first post operative year [3]. It is acknowledged that the majority of such deaths occur in the early post-operative period [4], [5], with the National Hip Fracture Database reporting a 30-day mortality rate of just over 8% [6], [7]. The arbitrary timeline of 30 days after surgery is commonly cited in many clinical and health related outcome publications as a surrogate quality indicator for proximal femoral care provision [8], [9], [10]. However, there is little corroborative evidence to validate this particular time period or to reflect upon the temporal impact of this injury.

Key non-modifiable factors are known to increase the risk of excessive mortality following proximal femoral fractures. These include age, male sex and anatomical position of the fracture, with a variable reported time period for increased mortality risk [11], [12], [13], [14]. Modifiable risk factors, such as chest infection and anaemia, might intuitively be expected to have a greater impact perioperatively because of the stress imposed by the fracture and its surgical treatment. However with time, such influences will lessen and the outcome should ultimately not be influenced by the inpatient episode. Accurate delineation of the duration of impact of trauma from injury and the following surgical procedure will allow the clinician to: (1) assess more accurately and reliably the impact of early intervention measures upon outcome and (2) separate the effects of intervention from the influence of high level of comorbidities associated with the natural history of these fractures.

This work has examined the survivorship out to one year of a consecutive series of patients admitted for proximal femoral fracture to a single institution. We aimed to quantify the temporal impact of the fracture upon mortality after surgery and in the context of mortality due to unrelated causes. We hypothesised that mortality after proximal femoral surgery was dependent on patient age, gender, surgical delay and length of stay. We tested a further hypothesis that mortality from cardiorespiratory causes would be higher perioperatively and that it would be dependent on patient age, time to surgery and length of stay.