With recent A&E waiting times historically high, Stuart McDonald and Natalie Tikhonovsky ask: is this causing additional deaths?
Since the summer of 2021, waiting times for admissions to accident and emergency (A&E) departments in the UK have exceeded seasonal norms and progressively worsened. That being the case, it is reasonable to question if patient outcomes may be affected. Might people be dying because of delays obtaining care?
We conducted an analysis to estimate the number of deaths attributable to recent long waiting times in England, as well as the contribution to recent ‘excess deaths’ by deducting the average number of deaths attributable to long waiting times pre-pandemic.
Data on waiting times
Jones et al.’s 2022 paper ‘Association between delays to patient admission from the emergency department and all-cause 30-day mortality’ examined the association between A&E wait duration and mortality risk for more than five million people admitted to hospital in England between April 2016 and March 2018. It accounted for many factors that influence mortality risk, such as age and comorbidities.
The analysis found that 30-day mortality increased for patients who were admitted to hospital after five hours. The rate increases in an approximately linear fashion from this point until statistically significant data is unavailable after 12 hours. It is estimated that there could be one additional death for every 82 patients waiting 6-8 hours and for every 72 patients waiting 8-12 hours.
To estimate the number of additional deaths compared to what might have been expected if there weren’t long A&E delays, we combined the published research with waiting time data.
NHS England publishes two measures of A&E waiting times (bit.ly/NHS_AE_admissions):
- Total time spent in A&E from arrival to discharge, transfer or admission
- Waiting time from the decision by a clinician to admit the patient to their admission (trolley wait).
We based our calculation on the number of long trolley waits, since the total waiting time data includes patients who were not ultimately admitted. Our analysis is limited to England, as we do not have trolley wait data for other UK nations.
The match between the data available and the research on harms arising is imperfect as we only have data showing whether waiting times exceeded four and 12 hours, whereas the research uses more granular categorisation of wait times.
Figure 1 shows the number of patients waiting more than four hours between the decision to admit them and their admission, broken down between those waiting 4-12 hours and those waiting 12 hours or more.
In the six months from September 2022 to February 2023, more than 866,000 patients waited more than four hours from the decision to admit. Of these, more than 246,000 waited 12 hours or more.
How many additional deaths?
We estimate the number of additional deaths arising from these delays by summing the following:
- Additional deaths from delays of 4-12 hours, calculated by dividing the number waiting 4-12 hours by the ‘number needed to harm’ for 6-8 hour delays (82)
- Additional deaths from delays of more than 12 hours, calculated by dividing the number waiting 12 hours or more by the ‘number needed to harm’ for 8-12 hour delays (72).
Since we do not have the distribution of waiting times for people waiting 4-12 hours, we assume that the average waiting time is in the 6-8 hour range. This seems reasonable and aligns with the observed distribution in Scotland, where slightly more granular data is published.
Our approach suggests that there were nearly 11,000 additional deaths in England in six months, which is more than 400 per week. This is expected to be an underestimate because we have made no allowance for the waiting time before the decision to admit the patient, and we have not allowed for extra harm arising when waits are more than 12 hours. Since the measure we have used is 30-day mortality, not all these deaths are occurring within A&E or even within the hospital setting.
Using our estimates of the number of additional deaths outlined above, we can then go on to estimate their contribution to recent excess deaths.
Excess deaths calculations typically compare mortality now to what was expected or observed during a prior period. There have always been some long delays in A&E departments, particularly during winter, but these have grown considerably longer since the summer of 2021.
To analyse the contribution that increased delays may be making to excess deaths, we can take the number of deaths arising from recent long delays and deduct the number arising from delays pre-pandemic, calculated in the same way. For this purpose we used the average for the same month in the 2015-19 period. This implies that the increase in long A&E delays contributed nearly 7,000 excess deaths between September 2022 and February 2023 – around 260 per week.
This is also likely to be an underestimate, for the same reasons as above. Furthermore, when the number of 12-hour delays is high, the average wait within the 4-12 hour band will be much higher than when there are very few 12 hour delays, as was the case during the pre-pandemic reference period. Our excess death calculation makes no allowance for the average 4-12 hour wait being longer.
Our approach draws heavily on a published study showing the association between delays to patient admissions and all-cause 30-day-mortality, so our conclusions depend on that study’s accuracy. This study was peer reviewed and has been widely cited. Our results also depend on the relationship between waiting times for admission to A&E and 30-day mortality being unchanged since the study period (2016-18). Plausibly, this might have changed if the case mix of patients is different.
Overall, our analysis suggests that a significant number of patients could be dying because of long delays accessing emergency care – we estimate more than 400 additional deaths each week between September 2022 and February 2023, though it might be higher. Not all of these are excess deaths, as typically defined, but all could be considered ‘avoidable’.
Stuart McDonald MBE is head of longevity and demographic insights at LCP
Natalie Tikhonovsky is an analyst at LCP Health Analytics
