This is the largest non-registry study of hip fracture mortality during the COVID-19 pandemic and highlights the excess mortality associated with concomitant COVID-19 infection in patients with hip fractures.
This study demonstrates a relative risk of death, within 30 days of hip fractures for COVID-19-positive patients, of 3.00 compared to COVID-negative patients. Current mortality prediction and scoring systems appear to significantly underestimate the mortality of these patients with the expected mortality exceeded by a factor of 3.
Despite the increase in 30-day mortality, surgical management remains the preferred treatment for hip fracture as non-operative management is known to be associated with poor outcomes . Our findings that excess deaths were reported during the COVID-19 outbreak in UK can help guide the prognosis of hip fractures during the pandemic.
The COVID-19 pandemic has posed significant challenges to healthcare, including access, infection complications and threat of iatrogenic transmission. Hip fractures occur most commonly in elderly people and preventing COVID-19 infection in this age group has unique challenges. Many patients are in residential or institutional care, thereby vulnerable to infection with close contact to care workers. The high caseload of COVID-19 in care homes, both in the UK and Europe, has highlighted the difficulties in containing outbreaks in the residential care environment. If the patients acquire COVID-19 infection during hospital admission, there is a potential risk of seeding a residential care outbreak as patients return back to nursing homes after their hospital episode. There is an urgent need to ensure mechanisms are in place for appropriate infection control to protect staff and other residents following hospital discharge.
There are several confounding factors which we have attempted to address. We have attempted to control for the significant heterogeneity of this patient population by matching the 2020 cohort to a 2019 cohort which has been shown to possess comparable demographics.
Theatre productivity has anecdotally changed since the pandemic. Our findings show a significant increase in operative delay in 2020 compared to 2019. This decrease in productivity is likely to persist as theatre complexes continue to adapt to aerosol generating procedures (AGPs). As our data collection commenced from the onset of the outbreak in the UK, theatre efficiency has undoubtedly improved as pathways for managing unscreened emergency patients were established. It is unlikely that such a significant relative risk is entirely caused by a modest operative delay, especially as the literature supports surgery within 48 hours rather than 36 [8, 24]. Furthermore, this study demonstrates a lower operative delay for the COVID-19-positive patients (22.1%) when compared to the 2019 cohort (40.8%) thereby mitigating this.
It is recognised that extracapsular fractures have a higher mortality than intracapsular fractures  and extracapsular fractures were more prevalent in the COVID-19-positive cohort from 2020 compared to the COVID-19-negative group. Given the magnitude of increase in relative risk observed in our COVID-19-positive group, fracture type is unlikely to be the sole explanation.
Research which relies on a database is subject to the completion of data. Our data ascertainment was 97.6% which we consider sufficient to not have confounded our findings.
>No UK healthcare institution commenced blanket screening of all emergency-admitted patients from the beginning of the pandemic. This relates to availability of testing materials and also the laboratory processing capacity. We accept that there may be asymptomatic or pre-symptomatic patients who were COVID-19 positive and survived but equally there may be patients within the COVID-19-negative cohort who died within 30 days unexpectedly. What our data does confirm is the increased risk to patients with hip fracture who have symptomatic COVID-19 infection.
It is accepted that in-hospital mortality for hip fracture patients is higher with general anaesthetic than neuraxial anaesthesia, though this is not represented in 30-day figures . Due to the lack of standardised anaesthetic protocols, the type of anaesthesia was not analysed and in addition was considered beyond the scope of this paper (Fig. 1).
Other confounding factors include potentially delayed presentation of patients due to apprehension regarding hospital attendance during the pandemic (which is likely to persist) and decreased availability of nursing and medical staff on the wards pre and post-operatively due to sickness levels amongst staff during the pandemic. These are very difficult to address and must be accepted as potentially confounding factors.
The COVID-19-positive cohort had significantly higher NHFSs and also a higher mean ASA grade. Whilst these parameters are suboptimal measures of general health , undoubtedly the cohort who became COVID-19 positive had more comorbidities. Whether infection is more prevalent in patients with more comorbidities or these patients are more likely to be symptomatic remains unclear. We do not propose the use of the NHFS as a predictive scoring system for patients contracting severe or symptomatic COVID-19.
Whilst elective surgical procedures are often proposed for a healthier cohort of patients, compared to hip fractures, there is definitive evidence that elderly patients with comorbidities have significantly increased mortality both with and without COVID-19 infection [19, 27]. All patients who are to undergo surgery, whether on an emergent or planned basis, should be informed of the risks and potentially defer surgery where possible.