METHODS
This paper has been prepared with reference to the STROBE checklist for
cross-sectional studies.
2.1. Ethical considerations
The Health Research Authority decision tool
(http://www.hra-decisiontools.org.uk/research/)
identified the project as service evaluation, which was approved by the
Applied Health in Cancer Governance Group at the lead NHS site.
Individual sites sought local approval to share data. A data flowchart
is attached as supplementary information.
2.2 Study design and setting
A national multi-centre audit of PTL was completed in response to the
Covid-19 pandemic over a six-month period (March to September 2020). The
background and development of the project has been described in detail
previously13. This is a secondary analysis of data
collected during the audit.
2.3 Participants
All PTL under the care of participating centres were eligible for
inclusion. Data were collected during the six-month period on PTL who
were reviewed by SLT either in person or via telehealth during the first
national lockdown.
2.4 Data collection
Data were obtained via case note review and survey questions. A data
capture worksheet (devised in Excel, password protected and encrypted)
was used to collect data. Personal identifying information was minimised
as advised by the information governance team. Verbal patient consent
was obtained whenever possible.
Data were collected on the potential explanatory variables described
above. The type of tracheostoma cover used was recorded at two time
points: before the onset of the Covid-19 pandemic (time point 1) and
during the six-month period of data collection (time point 2). This
paper reports on data collected from time point 1 to describe HME use
among PTL in the UK before the onset of Covid-19. Data on incidence of
Covid-19 infection, hospital admission and shielding advice were also
collected and have been reported previously13. Detailed analysis of factors influencing primary
communication method will be reported independently of this paper.
2.5 Data analysis
Analyses were carried out using SPSS for Windows. A univariable analysis
was initially performed to evaluate the association between each
potential explanatory variable and HME use, using Pearson’s chi-square
test for categorical variables and the two-sample t-test or Mann-Whitney
U test for continuous variables. Logistic regression analysis was
conducted to examine the association of selected variables with HME. A
backwards selection procedure was used to determine the final model
(criteria for entry p<0.05 and for removal
p>0.1). The overall fit of the model was ascertained using
the Hosmer and Lemeshow goodness of fit test.
RESULTS
3.1 Participants
Twenty-six centres across England and Wales submitted data for analysis.
Data were collected on a total of 1216 PTL. Details of the participating
centres and patient demographics are described in previous
work13.
3.2 HME vs non-HME use
Data on type of tracheostoma cover were available for 1097 PTL. The
majority (n= 835, 69%) used a closed-system HME. A range of alternative
tracheostoma covers was used by 17% (n=219). Only four percent (n=43)
were recorded as not using a tracheostoma cover (Table 1). For
subsequent analysis PTL were grouped into HME users (n= 835, 69%) or
non-HME users (n=262, 21%). One hundred and nineteen (10%) PTL were
excluded from further analysis due to missing data. Patient demographics
are illustrated in Table 2.
There was marked variation in the number of cases submitted for analysis
and the percentage of PTL using HME across centres (Figure 2). In two
centres (centres 1 and 19) 95% of PTL used a closed-system HME.
However, in four centres (3, 5, 13 and 26) less than 50% did so. The
amount of missing data also varied across centres. Centre 1 submitted
the largest number of cases (n=110) and also reported the highest HME
use, while centre 26 submitted only 3 cases with only 1 patient (33%)
using an HME. Centre 13 had the lowest HME use at 28% (n=12), but also
had a large amount of missing data (n=16, 37%).
3.3 Factors associated with HME use
In univariable analysis, age (p=0.02), gender (p=0.01), time elapsed
since surgery (p<0.0001), living circumstances (p=0.01) and
communication method (p<0.0001) demonstrated significant
differences between HME users and non-HME users. Distance from the
treating centre (p=0.92) and employment status (p=0.19) were not
significant factors.
Following multiple regression analysis, time elapsed since surgery
(p<0.001), living circumstances (p=0.003) and communication
method (p<0.001) remained statistically significant (Table 3).
Time elapsed since surgery was longer for non-HME users than for HME
users (median 108 months vs 59 months). Only 42% of PTL living in a
care facility used an HME, compared with 77% of those living with
someone or alone. SVR users were more likely to use an HME than non-SVR
users (80% vs 65%).
DISCUSSION
This is a novel study exploring HME usage among PTL in the UK. It
reports secondary analysis of data obtained in the UK national audit of
PTL carried out during the first national Covid-19 lockdown. To our
knowledge this is the largest audit of current practice in the
management of PTL and provides an important opportunity for
benchmarking. Our findings show that the majority of PTL (69%) included
in the audit used a closed-system HME. While this is a lower proportion
than has been quoted in previous studies5, HME usage
varied across centres from 28% to 95%. The centre with the largest
number of cases also reported the highest HME use, while many of those
centres with lower HME use also reported higher levels of missing data.
This may reflect SLT capacity and resources at those centres, and such
variability may indicate inequity of service across regions.
Although age was significant at univariable analysis, this was not
retained following multivariable analysis indicating that older PTL are
not disadvantaged in access to pulmonary rehabilitation. Similarly,
although males demonstrated higher use of HME than females (78% vs
69%) this was not significant in multivariable analysis. Employment
status and distance from the treating centre were not significant,
suggesting that these factors do not impact on access to rehabilitation
and advice or influence decision-making around humidification.
Factors found to be significantly associated with HME use in
multivariable logistic regression were time elapsed since surgery,
living circumstances and primary communication method.
4.1 Time elapsed since surgery
Average time post-surgery was 96 months, range 0-578 months. PTL who
were longer post-surgery were less likely to use an HME. Adherence to
HME use is improved with early introduction14,
therefore PTL who had surgery since closed-system HMEs have been widely
available on prescription are perhaps more likely to have commenced
early use and be ongoing HME users than those who had surgery before
this time. Average time elapsed since surgery for PTL with non-HME in
our study was nine years, and as HMEs have been available on
prescription since the mid-1990s it is clear that other factors are also
involved.
4.2 Living circumstances
Although previous studies have looked at factors that might predict
discharge destination following laryngectomy15, as far
as we are aware no study has looked at the impact of living
circumstances on HME use. We found that PTL living in a care facility
were significantly less likely to use an HME which may relate to wider
issues around the complexity of adherence to healthcare recommendations
in care facilities16 and has important implications
for the pulmonary health of this vulnerable group. Given HME use
involves specialist intervention and ongoing use of specialist
consumables, it may be that lower usage in care facilities indicates a
need for training and therapeutic input in this setting. Further
investigation is warranted.
4.3 Communication method
It is recognised that a closed-system HME supports improved digital
occlusion for voicing and better speech intelligibility for SVR
users8,9, therefore it may be expected that PTL with
SVR are more likely to use an HME. This is consistent with our findings.
This highlights the importance of pulmonary rehabilitation for non-SVR
users, who may receive less direct SLT intervention over time than those
PTL receiving regular input for voice prosthesis management.
4.4 Limitations of the study
This study reports on a range of factors that may influence HME use,
however there are additional factors that may account for the
variability identified. In order to optimise participation in the
audit a limited data set was selected, inevitably leading to a series of
unknowns. For example, we did not collect data on duration of HME use.
Full adherence is considered to be ≥20 hours per day17and various factors could influence this. We did not collect data on
barriers to HME use, whether HMEs are suitable for all PTL or on which
MDT member takes responsibility for pulmonary rehabilitation at each
centre. These factors could be explored in future work.
There was an amount of missing data in our study. It is not clear
whether this was due to pressure on the services providing data, reduced
contact with PTL due to the Covid-19 pandemic or other factors.
4.5 Future directions
Several professional organisations produced guidelines during the
Covid-19 pandemic that may have influenced advice given to patients
regarding humidification, including advice regarding the use of
specialist viral filter HMEs11,12,18. A survey of PTL
in the USA19 found that more patients reported
self-initiated changes to their HME use due to the pandemic than their
clinicians had advised. We note however that the ability of
closed-system HMEs to protect users against SARS-CoV-2 has not been
demonstrated. The current study presents data on HME use in the UK
pre-Covid-19 (time point 1). Future work could investigate behaviour
change as a result of the pandemic. The impact of social factors that
may outweigh clinician advice, such as the impact of marketing, social
media and peer influence19, could also be explored.
For the purpose of current analysis, PTL were divided into those using a
commercially available closed-system (“HME”) and all others
(“non-HME”). However, some researchers have found bibs to be superior
to closed-system HMEs in terms of humidity and
temperature3. Future work could explore factors
associated with the use of non-HMEs.
Our study identified marked variability in HME use across the UK, with
some centres reporting much higher HME use than others. The underlying
reasons for variation in practice could be examined to support equity of
access to pulmonary rehabilitation across centres.
Current findings suggest there may be education and training needs
around pulmonary rehabilitation for PTL who are less likely to use an
HME, such as those who are longer post-surgery, those living in care
facilities, and non-SVR users. This paper supports the need to target
education and training to ensure equity of access to pulmonary
rehabilitation for all PTL.
CONCLUSIONS
Across the UK, most PTL follow advice to use a closed-system HME to
maximise pulmonary health after surgical alteration to their upper
airway. Use of HMEs varies across participating treatment centres but
was found to be primarily impacted by certain factors: time elapsed
since surgery (PTL with a shorter time since surgery were more likely to
use an HME), living circumstances (PTL living in a care facility were
less likely to use an HME than those living alone or with someone) and
primary communication method (SVR users were more likely to use an HME
than PTL without SVR). The national average of 69% of PTL using an HME
serves as a benchmark for UK services. Education and training should be
targeted to ensure equity of access to pulmonary rehabilitation for all
PTL.
List of Tables and Figures:
Table 1: Type of tracheostoma cover used by PTL.
Table 2: Patient demographics, HME vs non-HME.
Table 3. Variables associated with HME use from Multivariable
Logistic Regression.
Figure 1: Types of tracheostoma cover.
Figure 2: HME vs non-HME use by centre.