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\begin{document}

\title{Validation of a Spanish Chronic Obstructive Sialadenitis Quality of Life
Questionnaire}



\author[1]{Jessica Mireya Santillán Coello}%
\author[1]{Alvaro Sanchez Barrueco}%
\author[2]{Fernando  González Galán}%
\author[2]{Gonzalo Diaz Tapia}%
\author[3]{Ignacio Mahillo Fernández}%
\author[4]{Carlos Cenjor Español}%
\author[4]{José Miguel Villacampa Aubá}%
\affil[1]{Universidad Alfonso X el Sabio}%
\affil[2]{Hospital General de Villalba}%
\affil[3]{Instituto de Investigacion Sanitaria de la Fundacion Jimenez Diaz}%
\affil[4]{Hospital Universitario Fundacion Jimenez Diaz}%


\vspace{-1em}



  
  \date{May 21, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
Objectives: To design a Spanish questionnaire to assess quality of life
in chronic obstructive sialadenitis (COS), named CSOC and assess its
reliability, validity and feasibility. Design: A prospective,
multicentre, observational study Settings: Salivary Gland Disorder and
Sialendoscopy Unit, University Tertiary Hospital. Participants: Patients
with diagnosis of COS and indication for sialendoscopy were included in
the study. Main outcome measures: The item generation process included a
review of published data as well as interviews with patients. An expert
panel then tested the content validity of the instrument and the
construct validity was tested in 120 patients. Patients completed a
self-administered CSOC questionnaire, a Short Form-36 and a Visual
Analogue Scale. Feasibility, reliability, internal consistency,
construct validity and responsiveness were assessed. Results: All the
patients found the instrument understandable. Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient was
high (0.85). The time required to fill out was 5.7 and 4.5 minutes for
pre and postsialendoscopy CSOC respectively. Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient was
very high for both pre and postsialendoscopy CSOC (0.90 and 0.94
respectively). The correlation with the SF-36 dimensions was negative
and positive with the VAS. The mean score of CSOC was 28.6 and 7.98 for
pre and postsialendoscopy Conclusions: The CSOC questionnaire is
understandable, feasible, reliable and representative of quality of life
in COS. Keywords: sialadenitis, QOL, questionnaire, validation,
sialendoscopy%
\end{abstract}%



\sloppy


\emph{Abstract}

\textbf{Objectives:} To design a Spanish questionnaire to assess quality
of life in chronicobstructive sialadenitis (COS), named CSOC and assess
its reliability, validity andfeasibility.

\textbf{Design} : A prospective, multicentre, observational study

\textbf{Settings:} Salivary Gland Disorder and Sialendoscopy Unit,
University Tertiary Hospital.

\textbf{Participants:} Patients with diagnosis of COS and indication for
sialendoscopy were included in the study.

\textbf{Main outcome measures:} The item generation process included a
review of published data as well as interviews with patients. An expert
panel then tested the content validity of theinstrument and the
construct validity was tested in 120 patients. Patients completed a
self-administered CSOC questionnaire, a Short Form-36 and a Visual
Analogue Scale. Feasibility, reliability, internal consistency,
construct validity and responsiveness were assessed.

\textbf{Results:} All the patients found the instrument understandable.
Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient was high (0.85). The time required to fill out
was 5.7 and 4.5 minutes for pre and postsialendoscopy CSOC respectively.
Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient was very high for both pre and postsialendoscopy
CSOC (0.90 and 0.94 respectively). The correlation with the SF-36
dimensions was negative and positive with the VAS. The mean score of
CSOC was 28.6 and 7.98 for pre and postsialendoscopy

\textbf{Conclusions:} The CSOC questionnaire is understandable,
feasible, reliable and representative of quality of life in COS.

\emph{Key points}\textbf{:}

\begin{itemize}
\tightlist
\item
  Chronic obstructive sialadenitis causes a marked loss in the quality
  of life.
\item
  Chronic obstructive sialadenitis and the results of sialendoscopy
  should be able to be evaluated by an objective tool.
\item
  Sialendoscopy, when possible, is currently the ideal treatment in
  chronic obstructive sialadenitis and the first therapeutic
  recommendation.
\item
  At this time, no statistically validated quality of life questionnaire
  applied to chronic obstructive sialadenitis has been described.
\item
  The first statistically validated quality of life questionnaire
  applied to the chronic obstructive sialadenitis and results of
  sialendoscopy is presented.
\end{itemize}



\textbf{Introduction}

Chronic obstructive sialadenitis (COS) is a benign disorder
characterized by repeated episodes of inflammation of the major salivary
glands{[}1--3{]}. Clinical presentation includes painful swelling of the
affected gland, usually trigged by meals or other means of salivary
stimulation. After years in which the disorder received scant attention
in research, the last decades have seen a growth in interest in the
results of minimally invasive treatment with sialendoscopy.

Patient-reported outcomes (PROs) can simplify patient involvement in
decision-making and may help healthcare professionals identify
patientconcerns{[}4{]}. PROs are also essential indicators in clinical
research and are frequently used as study endpoints{[}5{]}. Therefore,
there is an unmet need to develop a specific PRO to assess COS{[}6{]}.

To our knowledge, there are no existing Spanish questionnaires with
which to assess quality of life (QOL) in COS. We identified 3
English-language questionnaires specifically designed for COS and
sialendoscopy: Chronic Obstructive Sialadenitis Symptoms (COSS){[}2,
7--10{]}, Modified Oral Health Impact Profile-14 (OHIP-14){[}11{]}, and
patient satisfaction questionnaire{[}12{]}.

We are aware that for a QOL questionnaire to be used in clinical
practice or research, the instrument must be rigorously validated in
order to avoid incorrect interpretations.

Our purpose is to develop and validate a questionnaire to assess QOL in
COS -- called CSOC (Spanish acronym for \selectlanguage{ngerman}\emph{Cuestionario sobre Calidad
de vida en Sialoadenitis Obstructiva Crónica} ). The overall goal of
CSOC is to assess the impact of COS on QOL and the extent to which QOL
improves with sialendoscopy.

\textbf{Materials and Methods}

The study design and manuscript followed the STROBE reporting guideline.

\textbf{CSOC Questionnaire Development}

The developmental stage of a questionnaire consists of domain
identification, item generation, and instrument construction{[}13{]}.
Domain identification was accomplished by reviewing the published
literature. Four papers made reference to specific questionnaires (COSS
questionnaire{[}2, 7{]}, modified OHIP-14{[}11{]}, and patient
satisfaction questionnaire{[}12{]}) and 3 analysed findings generated by
applying generic QOL questionnaires (Glasgow Benefit Inventory{[}6,
14{]} and 5D-HRQoL{[}15{]}).

We chose health-related QOL as our domain of interest. The conceptual
definition of QOL selected was the level of well-being resulting from a
self-assessment of several dimensions of life and considering the impact
of these dimensions on health status{[}16{]}. The selected dimensions
were physical function and symptoms, performance of social roles,
occupational activities, emotional status, and how the patient feels
about their health.

The next step was to generate a list of potential items for each
dimension. After interviewing patients with COS, the research team
selected 20 items. Items were organized from specific conditions related
with sialadenitis to complaints related to overall health status.
Details of the CSOC questionnaire are shown in table 1.

Each item uses a Likert-type response scale (score 0-4). Lower scores
indicate better QOL in COS, whereas higher scores are suggestive of
greater degrees of impairment (Supplementary Table 1).

At the start of the questionnaire, patients were asked to score each
item based on their experience over the 3 preceding months. The research
group used this timeframe because of the intermittent and fluctuating
nature of COS symptoms according to their own experience.

\textbf{Study Population}

The ``Blinded for review'' approved all study proceedings (code
\emph{Blinded for review} ).

In the pilot study,the target for total enrolment was 30 participants in
order to achieve a reasonably high power (80\%), to detect a problem
that occurs in 5\% of the population, and pinpoint a repeat occurrence
of a problem that affects 10\% of the respondents{[}17{]}. Convenience
sampling was used to recruit subjects older than 18 years of age among
those patients with diagnosis of COS by an otolaryngologist and
indication for sialendoscopy evaluated at the department of
otorhinolaryngology at ``Blinded for review '' between June 2017 and
March 2018. COS was defined as at least 2 episodes of salivary gland
swelling and discomfort in the previous 3 months. We excluded patients
with a previous diagnosis of salivary glands tumour and those with
insufficient proficiency in the Spanish language.

Eight otolaryngologists experienced in sialadenitis management and
sialendoscopy from different hospitals and cities in ``Blinded for
review ''agreed to form part of the expert panel; members of the
research group were excluded. The size of the committee of experts was
determined based on recommendations contained in the literature{[}18{]}.

One hundred twenty patients were recruited for the validation study. The
sample size was calculated using the literature recommendationsof
including at least 5 subjects per item and not fewer than 100
subjects{[}19{]}. The inclusion and exclusion criteria were the same
used to assemble the sample for the pilot study. Patient were recruited
between July 2018 and July 2020.

\textbf{Study Procedures}

Pilot study: After providing written informed consent, participants
completed a self-administered CSOC questionnaire. After filling out the
CSOC, each patient was asked how well they had understood each item.

Content validity: We sent an e-mail to the experts alongside an
explanatory cover letter, reviewer instructions, definitions of terms,
and a content-review questionnaire. The members of the panel responded
by e-mail. In the content-review questionnaire, experts were asked to
judge how representative the questionnaire items are of QOL in COS using
a 4-point scale: 1 = not representative, 2 = somewhat representative, 3
= quite representative and 4 = highly representative. Experts were
prompted to evaluate the clarity of item construction and wording.
Finally, suggestions for addition or deletion of items were requested.

Validation process: After providing written informed consent,
participants completed a self-administered CSOC questionnaire at the
following time points:within45 days before sialendoscopy, in the
preoperative area before sialendoscopy and 90-120 days after
sialendoscopy. SF-36 and visual analogue scale (VAS)fordiscomfort were
completed at the first and third time points. The CSOC filled out during
the validation process comprised 18 items according to the results of
the pilot study and the content validityassessment (Supplementary Table
3).

\textbf{End Points}

The primary end points were to establish the comprehensibility,
feasibility, reliability, content,construct validity, and responsiveness
of the CSOC.

\textbf{Statistical Analysis}

Pilot study: Comprehensibility was calculated as the percentage of
patients who stated that the instrument was understandable. Feasibility
was assessed by examining the number of missing responses on the
returned questionnaires. Internal consistency analysis was performed
with the Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient.

A content validity index (CVI) based on expert ratings of relevance was
used to quantify content validity. We calculated the CVI for each item
(I-CVI) and for the overall scale (OS-CVI). The I-CVI was calculated as
the number of experts giving a rating of either 3 or 4, divided by the
number of experts. To determine OS-CVI, we calculated the I-CVI of each
item on the questionnaire and then computed the average I-CVI across
items{[}18{]} (Supplementary Table 2).

Validation process: Feasibility was assessed by examining the number of
missing responses on the returned questionnaires and the time required
to complete the questionnaire in minutes.A reliability analysis was
conducted, following the test-retest procedure. Internal consistency
analysis was performed with the Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient. Construct
validity was assessed using known groups validity and
convergent/divergent validity. The Mann-Whitney U test was used to test
for statistically significant differences between two subgroups of
frequency (fewer than 2 episodes and more than 4 episodes per week).
Convergent/divergent validity was assessed by correlating CSOC scores
with SF-36 and VAS using the Pearson correlation coefficient.
Responsiveness was evaluated comparing CSOC results before and after
sialendoscopy by paired sample t-test.

\textbf{Results}

Thirty participants were included in the pilot study. Sixty-three
percent were female, and their ages ranged from 18 to 62 years (median,
48 years). Half of the patients (50\%) had completed university studies,
and high school and primary school were the highest levels of education
completed by 40\% and 10\%, respectively. The number of missing items
from the CSOC was 0.

All the patients found the instrument understandable (100\%
comprehensibility). However, 5 patients expressed concern about items 14
and 15, as they believed they did not account for their individual
circumstances. These items inquired about work and academic activities,
and the patients who raised issues with these items were either
unemployed or retired. As a result, the research team included
recreational activities and basic activities of daily living in the
language of these items. The internal reliability for the 20 items was
high (Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient =0.85). The Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient showed
no improvement when individual items were deleted, meaning that no items
negatively affected the internal consistency of the CSOC.

Table 2 contains the results of the expert ratings of relevance for each
item. Items 5 and 6 were given an I-CVI of 0.63, meaning that they
should be considered for elimination. Items 4, 9 and 13 received an
I-CVI of 0.75, which indicates that further consideration should be
given to these. After it was confirmed that eliminating these items did
not affect internal consistency, the research group decided to exclude
items 5 and 6. The members of the research group reviewed items 4, 9,
and 13 (I-CV=0.75) and finally decided to maintain these in the second
phase of the validation process. The OS-CVI was 0.85 and if we eliminate
items 5 and 6, the OS-CVI increases to 0.88. One expert suggested
eliminating item 5, which also had a low I-CVI. The expert panel
suggested adding 3 items: (1) Presence of purulent or thick saliva; (2)
Difference between parotid and submandibular gland; and (3) Use of drugs
to relieve symptoms. The research group decided not to incorporate these
additional items. The presence of purulent or thick saliva is similar to
item 5, which was not considered to be representative. Differences noted
in the affected gland was not considered appropriate within a QOL
questionnaire. Finally, use of drugs to relieve the symptoms was
included as part of item 18.

Once the CSOC was modified in light of analytical findings and expert
feedback, the final version comprised 18 question (Supplementary Table
3) (total score 0-72).

One hundred and twenty subjects completed the presialendoscopy CSOC.
Seventy-three percent were female, and their median age was 48.3 years.
One hundred fifteen subjects (96\%) completed the postsialendoscopy CSOC
during the follow-up examination. The number of missing items from the
pre and postsialendoscopy CSOC was 0. The time required tofill out the
CSOC was 5.7 minutes (2-15 minutes) and 4.5 minutes (1-15 minutes) for
pre and postsialendoscopy CSOC respectively.

The reliability determined by test-retest washigh (interclass
correlation coefficient= 0.86, 95\% CI, 0.77-0.91). The internal
consistency for the 18 items was very high for both pre and
postsialendoscopy CSOC (Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient =0.90 and 0.94,
respectively). Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient showed no improvement when
individual items were deleted.

Significant differences were observed when the total CSOC score was
compared between 2 different groups of patients according with the
frequency of sialadenitis episodes during a week (fewer than 2 episodes
or more than 4 episodes).A greater difference was observed in
postsialendoscopy CSOC (table 3).

Figure1 shows the correlation coefficient between total CSOC score and
the different dimensions of SF-36 and VAS. The correlation with the
SF-36 dimensions was negative meaning that lower values of CSOC are
equal to higher values of SF-36. The correlation with VAS was positive.

The mean score for presialendoscopy CSOC was 28.6 (range, 3--61) and for
postsialendoscopy CSOC it was 7.98 (range,0-41).

\textbf{Discussion}

In a recent literature research, we identified 2 specific
English-language questionnaires used to assess QOL in patients with COS:
modified OHIP-14{[}11{]} and (COSS){[}2, 7--10{]}, one questionnaire to
assess patient satisfaction post sialendoscopy{[}12{]} and another
questionnaire (Multidisciplinary Salivary Gland Society (MSGS)
questionnaire) to quantify the burden of symptoms caused by xerostomia
and sialadenitis{[}20{]}.

The primary purpose of the present article was to design a specific
questionnaire in Spanish to assess QOL in patients with COS
(Supplementary Table 3) across six selected dimensions (physical
function and symptoms, social roles, occupational activities, emotional
status, and health perception). There are some similarities between
items of the CSOC and the Modified OHIP-14, COSS and MSGS. The patient
satisfaction questionnaire, on the other hand, is quite
different{[}12{]};it contains 14 questions that cover pre-sialendoscopy
symptoms, progress post-sialendoscopy, change in QOL, and overall
patient satisfaction and does not evaluate social roles, sleep
disorders, or emotional status{[}12{]}. The modified OHIP-14 was
designed to measure self-reported functional limitation, discomfort, and
disability in patients with salivary gland pathology{[}11{]}; the COSS
examines sialadenitis symptoms, daily functions, emotional symptoms,
sleeping and daily activities{[}7{]}; and the MSGSevaluatesxerostomia
and sialadenitis symptoms as well as their frequency, intensity, and
associated discomfort{[}20{]}.

As we can see, all 5 specific questionnaires measure the presence of
symptoms and functional limitations. The CSOC, modified OHIP-14{[}11{]},
and COSS{[}7{]} include items that target social roles. The CSOC and
modified OHIP- 14 assess emotional status. The CSOC includes
recreational activities to cover the whole occupational dimension. The
modified OHIP-14 has an item on work{[}11{]} that does not take
unemployed or retired people into account, and the COSS prompts
participants to provide information on daily activities in
general{[}7{]}. The COSS and CSOC have an item evaluating sleep.

A complete validation process was conducted with a pilot study as well
asassessment of content and construct validity. None of the existing
studies describes a process of content validity such as ours,which
includes an expert panel.

After the pilot study and assessment of content validity,the CSOC was
modified to include 18 items. The analysis of the new 18-items
psychometric properties suggested that CSOC has high feasibility
(absence of missing responses and around 5 minutes required to fill out
the questionnaire), high stability (test retest of 0.86), high internal
consistency (Cronbach \selectlanguage{greek}α \selectlanguage{english}coefficient of 0.90), and high responsiveness to
change. The absence of missing responses and the short time required
indicate that the responders found the CSOC to be easy to use. The
significant difference between the scores of pre- and postsialendoscopy
CSOC means that CSOC is a good tool to assess the improvement of COS
after sialendoscopy. Additionally, CSOC proved its capacity to
distinguish between patients with frequent and occasional episodes of
sialadenitis.

On the other hand, CSOC had a low to moderate negative correlation with
the different dimensions and component summaries of SF-36. The
correlation has the expected direction, and the low correlation could be
explained by the fact that SF-36 is not sensitive enough to capture the
difference in COS symptoms{[}2, 7{]}.

This study has three main limitations. First, we were unable to assess
criterion validity due to the lack of a validated gold standard test.
Second, we did not use a healthy control group. Third, the subjects used
for the validation process only represent those patients who have an
indication for sialendoscopy; to validate CSOC for all COS patients, a
study which includes patients with and without indication for
sialendoscopy should be conducted.

\textbf{Conclusion}

To date, there is no validated questionnaire that addresses QOL in
patients with COS. Also, there is no specific Spanish questionnaire to
assess QOL in COS. The CSOC questionnaire is an understandable,
feasible, validated, and reliable instrument measuring QOL in COS.

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19. Morales Vallejo P Tamaño necesario de la muestra: ¿Cuántos sujetos
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https://doi.org/10.1002/lary.29731\selectlanguage{english}
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