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\begin{document}

\title{Safety of day-case endoscopic sinus surgery in England: An observational
study using an administrative dataset}



\author[1]{Annakan Navaratnam}%
\author[2]{Alfonso Pendolino}%
\author[3]{Peter J Andrews}%
\author[4]{Hesham Saleh}%
\author[5]{Claire Hopkins}%
\author[2]{prem randhawa}%
\author[6]{Sarah Little}%
\author[7]{Jamie Day}%
\author[7]{Tim Briggs}%
\author[7]{William Gray}%
\affil[1]{Imperial College Healthcare NHS Trust}%
\affil[2]{Royal National Throat Nose and Ear Hospital}%
\affil[3]{University College London Hospitals NHS Foundation Trust}%
\affil[4]{Charing Cross Hospital}%
\affil[5]{Guy's and St Thomas' Hospitals NHS Trust}%
\affil[6]{St Georges’ Hospital}%
\affil[7]{NHS England and NHS Improvement London}%


\vspace{-1em}



  
  \date{May 24, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
Background: As elective surgical services recover from the COVID-19
pandemic a movement towards day-case surgery may reduce waiting lists.
However, evidence is needed to show that day-case surgery is safe for
many ENT operations including endoscopic sinus surgery (ESS). We aimed
to investigate the safety of ESS in England. Methods: This was an
observational, secondary analysis of administrative data. Participants
were all patients in England undergoing elective ESS procedure aged [?] 17
years during for the five years from 1st April 2014 to 31st March 2019.
The exposure variable was day-case or overnight stay. The primary
outcome was emergency readmission within 30 days post-discharge.
Results: Data were available for 49,223 patients operated on across 129
NHS hospital trusts. In trusts operating on more than 50 patients in the
study period, rates of day-case surgery varied from 100\% to 20.6\%.
Rates of day-case surgery increased from 64.0\% in 2014/15 to 78.7\% in
2018/19. Day-case patients had lower rates of 30-day emergency
readmission (odds ratio 0.71, 95\% confidence interval 0.62 to 0.81).
For secondary outcomes measures, there was no evidence of poorer
outcomes for day-case patients. Outcomes for patients operated on in
trusts with [?]80\% day-case rates compared to patients operated on in
trusts with \textless{}50\% rates of day-case surgery were similar.
Conclusions: ESS can safely be performed as day-case surgery at current
rates. There is a potential to increase rates of day-case ESS in
England, especially in departments that currently have low rates of
day-case ESS.%
\end{abstract}%



\sloppy


\textbf{Key points}

\begin{itemize}
\tightlist
\item
  A total of 49,223 patients underwent endoscopic sinus surgery in
  England between April 2014-March 2019.
\item
  Rates of day-case surgery varied from 100\% to 20.6\% across hospital
  trusts.
\item
  There was no evidence of poorer outcomes for day-case patients.
\item
  Day-case endoscopic sinus surgery appears to be safe when conducted as
  day-case surgery.
\item
  Hospital trusts not already conducting day-case endoscopic sinus
  surgery as the default, should move to a day-case model to improve
  service efficiency.
\end{itemize}



\textbf{ABSTRACT}

\textbf{Background:} As elective surgical services recover from the
COVID-19 pandemic a movement towards day-case surgery may reduce waiting
lists. However, evidence is needed to show that day-case surgery is safe
for many ENT operations including endoscopic sinus surgery (ESS). We
aimed to investigate the safety of ESS in England.

\textbf{Methods:} This was an observational, secondary analysis of
administrative data. Participants were all patients in England
undergoing elective ESS procedure aged [?] 17 years during for the five
years from 1\textsuperscript{st} April 2014 to
31\textsuperscript{st}March 2019. The exposure variable was day-case or
overnight stay. The primary outcome was emergency readmission within 30
days post-discharge.

\textbf{Results:} Data were available for 49,223 patients operated on
across 129 NHS hospital trusts. In trusts operating on more than 50
patients in the study period, rates of day-case surgery varied from
100\% to 20.6\%. Rates of day-case surgery increased from 64.0\% in
2014/15 to 78.7\% in 2018/19. Day-case patients had lower rates of
30-day emergency readmission (odds ratio 0.71, 95\% confidence interval
0.62 to 0.81). For secondary outcomes measures, there was no evidence of
poorer outcomes for day-case patients. Outcomes for patients operated on
in trusts with [?]80\% day-case rates compared to patients operated on in
trusts with \textless{}50\% rates of day-case surgery were similar.

\textbf{Conclusions:} ESS can safely be performed as day-case surgery at
current rates. There is a potential to increase rates of day-case ESS in
England, especially in departments that currently have low rates of
day-case ESS.

\textbf{Keywords:} Endoscopic sinus surgery, ear, nose and throat
surgery, day-case surgery.



\textbf{INTRODUCTION}

As elective surgery services recover from the COVID-19 pandemic the rate
of return to normal activity levels has been slower for ear, nose and
throat (ENT) surgery than for other specialties in a number of
countries.\textsuperscript{1,2} Concerns regarding spread of COVID-19
during potentially aerosol generating procedures such as endoscopic
sinus surgery (ESS) may have influenced this.\textsuperscript{3,4} As
elective ENT services now look to reduce the patient backlog, efficient
working practice will be essential.

For certain groups of patients undergoing relatively low-risk
procedures, day-case surgery may be part of the solution. In ENT surgery
in England, prior to the COVID-19 pandemic, a number of hospital trusts,
had moved to a model of day-case surgery as the default for low risk
patients and low complexity procedures, including
ESS.\textsuperscript{5}

In England, The Getting It Right First Time (GIRFT) programme has a
remit to reduce unwarranted variation in clinical practice where this
impacts negatively on patient outcomes or service efficiency. Variation
in rates of day-case surgery is an area of particular
interest.\textsuperscript{6,7} Key barriers to increasing day-case rates
identified by the GIRFT ENT national report were a cultural reluctance
to change practice, a lack of day-case infrastructure, a concern that
outcomes would be compromised and a sense that their day-case rates were
already 'optimal' for their patient population.\textsuperscript{5}

The aim of this study was to investigate the safety of day-case ESS
within the National health Service (NHS) in England using a national
administrative dataset.

\textbf{METHODS}

\textbf{Study design}

This was a retrospective analysis of administrative data from the UK
Hospital Episode Statistics (HES) database. The HES database is
collected by NHS Digital and included data for all NHS hospital activity
in England. Reporting follows the recommendations of the format of the
Strengthening of Reporting of Observational studies in Epidemiology
(STROBE) guidelines.

\textbf{Ethics}

The presentation of data follows current NHS digital guidance for use of
HES data for research purposes.\textsuperscript{8} Consent from
individuals involved in this study was not required for analysis of this
administrative dataset.

\textbf{Data extraction}

Setting

All NHS hospitals in England are run by trusts. Each trust covers a
geographically defined catchment area of varying physical size and
population. A single trust typically runs between one and four large
secondary or tertiary care hospitals.

Time period

1\textsuperscript{st} April 2014 to 31\textsuperscript{st} March 2019
for the index procedure with follow up of all patients for one year
post-surgery.

Inclusion and exclusion criteria for index procedure

We identified ESS using the Office of Populations Censuses and Surveys
Classification of Interventions and Procedures version 4 (OPCS-4) codes:
E081, E132, E133, E142, E143 or E148 were used in the first position in
the procedural record together with the code Y761 (for functional ESS)
anywhere in the procedural record. Descriptions of the definitions of
these codes are given in \textbf{Supplementary material Table
S1.}Patients were only included if the clinical specialty listed was
ENT.

Patients were also excluded where:

\begin{enumerate}
\tightlist
\item
  The procedure was non-elective
\item
  The patient was aged \textless{}17 years.
\item
  Patients with a diagnosis of any of the following conditions anywhere
  in the diagnostic record for the index admission: malignant neoplasm,
  vasculitis, granulomatosis intracranial and intraspinal abscess and
  granuloma, granuloma and granuloma-like lesions of oral mucosa, cystic
  fibrosis, diseases of bronchus and cerebrospinal fluid leak without
  diagnosis of sinusitis or nasal polyp. Patients undergoing
  trans-sphenoidal pituitary surgery were also excluded. The OPCS-4 and
  International Statistical Classification of Diseases and Related
  Health Problems, tenth revision (ICD-10) codes used to define these
  procedures are given in \textbf{Supplementary material Table S1} .
\end{enumerate}

Patients with malignant neoplasm and with the other conditions described
would not routinely be considered for day-case surgery, although some
are likely to be suitable for, and undergo day-case surgery.

To ensure all datapoints were independent of one another at a patient
level, only the chronologically first recorded index procedure for
anyone who had more than one procedure during the study period was
included in the dataset. The data extraction process is summarised
in\textbf{Supplementary material Figure S1} .

\textbf{Primary outcome}

Emergency hospital readmission within 30 days of discharge. This outcome
was chosen to reflect the need for an early readmission related to a
complication of surgery.

\textbf{Secondary outcome}

\begin{enumerate}
\tightlist
\item
  Repeat ESS in any subsequent admission within 180 days of discharge
  from the index procedure. The same OPCS-4 codes listed above for ESS
  were used to define repeat surgery. This follow-up period was chosen
  to allow sufficient time for complications of index surgery to arise,
  but to avoid cases of planned repeat surgery.
\item
  Mortality at one year post-discharge. Mortality data were taken from
  the UK Office for National Statistics (ONS).
\item
  Likely complications of surgery identified during emergency admission
  within 30 days post-discharge. These complications were defined within
  five broad categories: haemorrhage, orbital injury, cerebrospinal
  fluid leak, meningitis, other post-procedural complication. The ICD-10
  codes used to define these complications are given
  in\textbf{Supplementary material Table S1} .
\item
  Haemorrhage was the most common recorded complication and was also
  considered separately.
\end{enumerate}

\textbf{Exposure variables}

\textbf{Primary exposure variable:} Day-case or overnight stay. Day-case
was defined as any procedure where the admission day and discharge day
were the same.

\textbf{Secondary exposure variable:} In secondary analysis the exposure
variable was defined at a trust level; trusts operating on [?] 80\% of
patients as day-case and trusts operating on \textless{} 50\% of
patients as day-case were compared. Eighty percent was chosen to reflect
trusts where day-case surgery appeared to be the default and 50\% was
chosen to reflect trusts where surgery with overnight stay was dominant.
This analysis was conducted to minimise bias, when considering the data
at a patient level due to patients with more severe illness (and so
potentially poorer outcomes) being more likely to stay in overnight. For
this analysis, trusts performing fewer than 50 procedures over the study
period (average of ten per financial year) were excluded.

\textbf{Covariates}

\begin{enumerate}
\tightlist
\item
  Age in years
\item
  Sex
\item
  Financial year of admission
\item
  Hospital Frailty Risk Score (HFRS)\textsuperscript{9}
\item
  Complex ESS: Complex surgery was defined using any occurrence of any
  of the OPCS-4 codes E143, E147, E148, E151, E152
  (see\textbf{Supplementary material Table S1} for descriptions).
\item
  Diagnosis during index admission of obesity (ICD-10 code: E66-)
\item
  Diagnosis of any of the 17 conditions that make up the Charlson
  comorbidity index\textsuperscript{10}
\item
  Likely complications of surgery identified during the index admission.
  Complications were defined as described above for the outcome
  measures. This covariate was chosen in recognition of the fact that a
  complication identified during the index procedure would, in many
  cases, preclude same-day discharge and be associated with poorer
  post-discharge outcomes.
\end{enumerate}

\textbf{Data management and statistical analyses}

Data were analysed using standard statistical software: Microsoft Excel
(Microsoft Corp, Redmond, WA, USA), Stata (Stata Corp LLC, College
Station, TX, USA) and Alteryx (Alteryx Inc, Irvine, CA, USA).

Age data were broadly normally distributed on visual inspection and
summarised using the mean and standard deviation. All other data were
categorical and were summarised using frequency and percentage.
Multilevel (hierarchical) logistic regression models were constructed.
All variables were treated as categorical in model building except age,
which was modelled as a continuous variable using restricted cubic
splines; knots (at the 10\textsuperscript{th}, 50\textsuperscript{th}and
90\textsuperscript{th} percentile) were found to give optimal model fit
for the primary outcome based on Akaike's Information
Criterion.\textsuperscript{11} Adjusted outcomes were calculated based
on fixed-effects within a conditional framework. Confidence intervals
(CIs) were used to draw inference, with a 95\% CI for an odds ratio (OR)
not including the value 1 taken to indicate significance.

\textbf{RESULTS}

The extraction process identified 49,223 ESS procedures during the study
period. The procedures were performed across 129 hospital trusts.
Day-case surgery was conducted for 35,494 (72.1\%) patients. The
characteristics and outcomes for patients seen as day-case and with
overnight stay are summarised in \textbf{Table 1} . Patients with an
overnight stay were on average three years older than day-case patients
and more likely to have some level of frailty. Outcomes tended to be
slightly poorer for overnight stay patients, most notably for
complications (including haemorrhage) recorded during the index
admission. Such complications are likely to have necessitated overnight
stay in many cases. Although the one-year mortality rate was higher for
patients with an overnight stay, this partly reflects the older age
structure of the population. Mortality rates were low.

Of the 121 trusts that conducted more than 50 procedures across the
five-year study period, 42 trusts (14,186 patients) performed [?]80\% of
procedures as day-case and 15 trusts (4,634 patients) performed
\textless{}50\% of procedures as day-case. In these 121 trusts, the
highest rate of day-case surgery was 100\% in three trusts (561
patients) and the lowest rate was 20.6\% (n = 170 patients) in one
trust. The distribution of day-case rates for each trust is summarised
as a funnel plot in \textbf{Figure 1} .

There was a substantial increase in the proportion of procedures
conducted as day-case across the study period, from 64.0\% in financial
year 2014/15 to 78.7 \% in financial year 2018/19. Despite this increase
in the overall rate of day-case surgery, in financial year 2018/19,
seven trusts still performed fewer than 50\% of ESS procedures as
day-case. The proportion of patients seen as day-case and their outcomes
are shown in \textbf{Table 2} . Patient outcomes were generally stable
across the five-year period, with no clear trend.

The results of the multilevel, multivariable models comparing outcomes
for day-case and overnight stay patients are presented in \textbf{Table
3} . The odds of poorer outcomes were generally lower for day-case
patients after adjusting for covariates and in the case of 30-day
emergency readmission, one-year return for ENT surgery and 30-day
complications significant. The results of the analysis comparing trusts
with high and low rates of day-case surgery are presented
in\textbf{Table 4} . There was no significant difference in outcomes
between high and low day-case rate trusts.

\textbf{DISCUSSION}

Day-case ESS activity in England has risen substantially over the last
20 years with a greater than four-fold increase in day-case rates; from
15.5\% in 2000-01\textsuperscript{12} to nearly 80\% in 2018-19. We
provide evidence that day-case ESS is safe. There was no evidence that
outcomes were better for patients with overnight stay. Generally better
outcomes for patients undergoing day-case surgery are likely to be due,
in part, to confounding factors not fully adjusted for through
modelling, most obviously disease severity. Our comparison of trusts
with high and low rates of day-case surgery attempts to overcome this
residual confounding, since presentation is unlikely to vary between the
two groups of trusts in a way that would substantially bias our
findings. In this analysis there was no significant difference between
the two groups. It is also interesting that, despite a substantial
increase in the proportion of patients undergoing day-case ESS over the
five-year, outcomes were relatively stable over time.

Most previous studies on the safety of day-case ESS are relatively
small. A study of outcomes from 909 rhinology procedures published in
2021 reported no difference in readmission rate between outpatient
(day-case) and inpatient groups.\textsuperscript{13} The authors noted
higher complication rates in those with overnight stay, highlighting
differences in patient selection criteria for day-case
surgery.\textsuperscript{13} Nevertheless, the conversion rate from
day-case to overnight stay was less than 5\%. A single surgeon study of
181 patients (both day-case and overnight stay) from New Zealand
concluded that day-case sinonasal surgery was safe and acceptable to
patients.\textsuperscript{14} An earlier case note review involving 105
day-case ESS patients drew similar conclusions and suggested important
factors in successful implementation of day-case ESS were careful
patient selection and dedicated day-case
infrastructure.\textsuperscript{15} A French study focussing on patient
reported outcomes for endoscopic ethmoidectomy reported no readmission
and no major complications in their series of 74 patients. SNOT-22
scores decreased on average by 56\% post-operatively, demonstrating good
surgical outcomes in day-case ESS.\textsuperscript{16}

One of the reasons often cited for the need to have an overnight
observation following ESS, other than patient co-morbidities, is the
risk of post-operative haemorrhage.\textsuperscript{12} However,
advances in ESS techniques have led to reduced morbidity associated with
the procedure. Furthermore, the utilisation of topical vasoconstrictor
agents, antifibrinolytic medications and hypotensive anaesthetic
practice have contributed to reduced intra-operative and post-operative
bleeding, supporting a day-case model.\textsuperscript{17,18} We found
relatively low rates of haemorrhage during the index procedure (0.5\%
(day-case) and 4.3\% (overnight stay)) compared to an earlier large
prospective cohort study of ESS in England and Wales that reported
excessive perioperative bleeding rates of 5\% and post-operative
haemorrhage rates of 1\%.\textsuperscript{19} Some of these differences
may be due to differences in data collection (coded events vs surgeon
reported). The indication for overnight stay for many patients is likely
to have been excessive perioperative or immediate post-operative
haemorrhage, explaining the higher haemorrhage rate in this group.
Recent increases in the use of absorbable packing also enables patients
to be discharged with nasal packing still in situ if post-operative
minor haemorrhage is a concern.\textsuperscript{20,21}

There remains substantial variation between NHS hospital trusts in
England in rates of day-case ESS. In the last full financial year prior
to the COVID-19 pandemic a number of trusts still had overnight stay for
the majority of patients. The barriers to day-case ESS can be cultural
as well as practical. Surgical preference and trust policy can hinder
attempts to create an effective day surgery pathway. Careful theatre
management that takes into account operation timing and case-mix will
help optimise day-case surgery potential.\textsuperscript{13} The
proximity of the patient's home address need not be an absolute
contraindication to day-case surgery. In France, non-medical
accommodation has been offered to patients travelling a long distance
for their surgery.\textsuperscript{13} Such provision is substantially
less costly that a hospital bed. Day-case surgery can support more
cost-effective and resource-efficient provision of surgical services by
preventing unnecessary bed occupation\textsuperscript{14} and reducing
risks of hospital acquired infection and
deconditioning.\textsuperscript{22}

A further consideration that will impact the surgical management of
sinonasal disease is the emergence of balloon sinuplasty which can be
performed under local anaesthetic, and therefore as a day-case or
out-patient office procedure.\textsuperscript{23} Complication risks are
similar to those of conventional ESS.\textsuperscript{24} Although not
indicated for all patients, identifying patients that would benefit from
this procedure may help reduce ESS waiting lists.\textsuperscript{25}

The ability to track patients across hospitals in England and the
comprehensiveness of the HES database are strengths of our study.
However, the lack of data relating to some aspects of clinical
presentation limited the extent to which we could adjust for this. Some
data entry inconsistencies between trusts have been noted, mostly with
regard to differences in clinical coding practice across
trusts.\textsuperscript{5} However, coding for ESS is relatively
uncomplicated and so may be less prone to such errors. Data on patient
quality of life and other patient reported outcomes were not available
and would have added markedly to the depth of our findings.

\textbf{Conclusions}

Our study provides evidence that outcomes for day-case and overnight
stay ESS are similar. Although not indicated for all patients, day-case
surgery will be appropriate for large numbers of patients and should be
utilised where possible to improve patient experience and hospital
productivity.

\textbf{References}

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21. Wang TC, Tai CJ, Tsou YA, Tsai LT, Li YF, Tsai MH. Absorbable and
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22. Munnich EL, Parente ST. Procedures take less time at ambulatory
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24. Chaaban MR, Rana N, Baillargeon J, Baillargeon G, Resto V, Kuo YF.
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\textbf{Figure legends}

\textbf{Figure 1: Variation in the day-case rate by hospital trust}

Note: The inner control limits represent two standard errors and the
outer control limits three standard errors from the England average.
This funnel plot demonstrates that there is wide variation in day-case
rate ESS, especially in trusts that performed less than 400 ESS
procedures over the 5 year time period.



\textbf{Table 1: Profile of all patients undergoing endoscopic sinus
surgery}\selectlanguage{english}
\begin{longtable}[]{@{}lll@{}}
\toprule
\textbf{Variable} & \textbf{Day-case (n = 35,494)} & \textbf{Overnight
stay (n = 13,729)}\tabularnewline
\midrule
\endhead
Mean age in years (standard deviation) & 49.7 (14.845) & 52.6
(15.475)\tabularnewline
Number of males (\%), 3 missing values & 20959 (59.1\%) & 8137
(59.3\%)\tabularnewline
Hospital Frailty Risk Score & &\tabularnewline
\emph{None} & 33327 (93.9\%) & 12313 (89.7\%)\tabularnewline
\emph{Mild} & 1842 (5.2\%) & 1082 (7.9\%)\tabularnewline
\emph{Moderate} & 309 (0.9\%) & 310 (2.3\%)\tabularnewline
\emph{Severe} & 16 (0.1\%) & 24 (0.2\%)\tabularnewline
Number of patients undergoing complex ESS & 7482 (21.1\%) & 3189
(23.2\%)\tabularnewline
Emergency hospital readmission within 30 days of discharge & 723 (2\%) &
428 (3.1\%)\tabularnewline
Return for ESS within 180 days of discharge & 229 (0.6\%) & 85
(0.6\%)\tabularnewline
Death within one year of discharge & 81 (0.2\%) & 63
(0.5\%)\tabularnewline
Any complications recorded during index stay & 344 (1.0\%) & 836
(6.1\%)\tabularnewline
Haemorrhage recorded during index stay & 164 (0.5\%) & 588
(4.3\%)\tabularnewline
Orbital injury recorded during index stay & 97 (0.3\%) & 87
(0.6\%)\tabularnewline
Cerebrospinal fluid leak recorded during index stay & 2 (0.01\%) & 18
(0.1\%)\tabularnewline
Meningitis recorded during index stay & 0 & 0\tabularnewline
Any complications recorded on emergency readmission within 30 days of
discharge & 425 (1.2\%) & 222 (1.6\%)\tabularnewline
Haemorrhage recorded on emergency readmission within 30 days of
discharge & 305 (0.9\%) & 153 (1.1\%)\tabularnewline
Orbital injury recorded on emergency readmission within 30 days of
discharge & 30 (0.1\%) & 11 (0.1\%)\tabularnewline
Cerebrospinal fluid leak recorded on emergency readmission within 30
days of discharge & 1 (0.003\%) & 5 (0.04\%)\tabularnewline
Meningitis recorded on emergency readmission within 30 days of discharge
& 3 (0.01\%) & 3 (0.02\%)\tabularnewline
\bottomrule
\end{longtable}



\textbf{Table 2: Change in proportion of patients operated on as
day-case and outcomes over the five-year study period}\selectlanguage{english}
\begin{longtable}[]{@{}llllll@{}}
\toprule
\textbf{Financial year} & \textbf{2014/15} & \textbf{2015/16} &
\textbf{2016/17} & \textbf{2017/18} & \textbf{2018/19}\tabularnewline
\midrule
\endhead
Number of patients & 10105 & 10029 & 10371 & 9649 & 9069\tabularnewline
Number of patients as day-case & 6471 (64.0\%) & 6937 (69.2\%) & 7575
(73\%) & 7376 (76.4\%) & 7135 (78.7\%)\tabularnewline
Number of patients undergoing complex ESS & 2291 (22.7\%) & 2159
(21.5\%) & 2252 (21.7\%) & 2086 (21.6\%) & 1883 (20.8\%)\tabularnewline
Emergency readmission within 30 days of discharge & 207 (2.0\%) & 230
(2.3\%) & 259 (2.5\%) & 219 (2.3\%) & 236 (2.6\%)\tabularnewline
Return for ESS within 180 days of discharge & 67 (0.7\%) & 74 (0.7\%) &
69 (0.7\%) & 39 (0.4\%) & 65 (0.7\%)\tabularnewline
Death within one year of discharge & 33 (0.3\%) & 31 (0.3\%) & 35
(0.3\%) & 25 (0.3\%) & 20 (0.2\%)\tabularnewline
Any complications recorded during index stay & 232 (2.3\%) & 224 (2.2\%)
& 251 (2.4\%) & 213 (2.2\%) & 260 (2.9\%)\tabularnewline
Haemorrhage recorded during index stay & 162 (1.6\%) & 160 (1.6\%) & 153
(1.5\%) & 134 (1.4\%) & 143 (1.6\%)\tabularnewline
Any complications recorded on emergency readmission within 30 days of
discharge & 119 (1.2\%) & 128 (1.3\%) & 140 (1.3\%) & 123 (1.3\%) & 137
(1.5\%)\tabularnewline
Haemorrhage recorded on emergency readmission within 30 days of
discharge & 90 (0.9\%) & 92 (0.9\%) & 97 (0.9\%) & 87 (0.9\%) & 92
(1\%)\tabularnewline
\bottomrule
\end{longtable}

\textbf{Table 3: Summary of multilevel, multivariable models of the
relationship between day-case surgery and outcomes}\selectlanguage{english}
\begin{longtable}[]{@{}ll@{}}
\toprule
\textbf{Outcome} & \textbf{Odds ratio (95\% confidence
interval)}\tabularnewline
\midrule
\endhead
Emergency readmission within 30 days of discharge & 0.71 (0.62 to
0.81)\tabularnewline
Return for ESS within 180 days of discharge & 1.12 (0.86 to
1.46)\tabularnewline
Death within one year of discharge & 0.79 (0.55 to 1.12)\tabularnewline
Complications recorded on emergency readmission within 30 days of
discharge & 0.79 (0.66 to 0.94)\tabularnewline
Haemorrhage recorded on emergency readmission within 30 days of
discharge & 0.86 (0.69 to 1.05)\tabularnewline
\bottomrule
\end{longtable}

Note: An odds ratio less than 1 indicates that the outcome was less
common for patients undergoing day-case surgery and an odds ratio
greater than 1 indicates that the outcome was more common for patients
undergoing day-case surgery. A 95\% confidence interval which does not
cross the value 1 indicates statistical significance at the 5\% level.

\textbf{Table 4: Summary of multilevel, multivariable models of the
relationship between trusts with high and low rates of day-case surgery
and outcomes}\selectlanguage{english}
\begin{longtable}[]{@{}ll@{}}
\toprule
\textbf{Outcome} & \textbf{Odds ratio (95\% confidence
interval)}\tabularnewline
\midrule
\endhead
Emergency readmission within 30 days of discharge & 1.15 (0.86 to
1.53)\tabularnewline
Return for ESS within 180 days of discharge & 1.48 (0.83 to
2.66)\tabularnewline
Death within one year of discharge & 1.34 (0.72 to 2.49)\tabularnewline
Complications recorded on emergency readmission within 30 days of
discharge & 1.50 (0.99 to 2.25)\tabularnewline
Haemorrhage recorded on emergency readmission within 30 days of
discharge & 1.57 (0.98 to 2.52)\tabularnewline
\bottomrule
\end{longtable}

Note: Odds ratios refer to the odds of the outcome in trusts with a
day-case rate [?] 80\% relative to a trust with day-case rates \textless{}
50\% (reference group). An odds ratio less than 1 indicates that the
outcome was less common for high day-case rate trusts and an odds ratio
greater than 1 indicates that the outcome was more common for high
day-case rate trusts. A 95\% confidence interval which does not cross
the value 1 indicates statistical significance at the 5\% level.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Figure-1-(300-x-300-dpi)/Figure-1-(300-x-300-dpi)}

\end{center}
\end{figure}

\selectlanguage{english}
\FloatBarrier
\end{document}

