Development and Validation of a Health Behaviour Theory-based Questionnaire to Explore the Willingness of Older Adults and Informal Caregivers to Deprescribe
Conditions: Psychological
Sponsor: Université Catholique de Louvain

N°:AAHRPP-DSQ-038     REV 003 
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"Please do take into account that this is a translation of the original French version 
validated in the Quality Management System (QMS) of Cliniques universitaires Saint-Luc 
through the SharePoint PaCo GED. Therefore in case of doubt, differences, inconsistency 
or discrepancy in this English version, the French version shall prevail" 
 
 
 
POLICY -  NON-INTERVENTIONAL OR 
RETROSPECTIVE CLINICAL STUDY 
PROTOCOL TEMPLATE  
N° : AAHRPP-DSQ-038 / REV002 
N° ENGLISH VERSION : 012 

Development and validation of a health behaviour theory-based questionnaire to explore the 
willingness of older adults and informal caregivers to deprescribe (HBQtD) 
 
Protocol II– dated on 2023/08/11 
 
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1. TITLE PAGE  
 
Development and validation of a health behaviour theory-based questionnaire to assess the 
willingness of older adults and informal caregivers to deprescribe (HBQtD) 
 
Protocol identification: HBQ23 
Sponsor: UCLouvain (ARC, Actions de Recherche Concertée) 
 
 

Development and validation of a health behaviour theory-based questionnaire to explore the 
willingness of older adults and informal caregivers to deprescribe (HBQtD) 
 
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This study is an instrument development and validation project that will last about a year. 
Sponsor: UCLouvain (ARC-Di-Prescribe), Place de l’Université 1, 1348 Louvain-la-Neuve 
Sponsor representative:  Professor Spinewine, LDRI Avenue Mounier 72/B1.72.02 1200 Woluwe-
Saint-Lambert; phone number: +32 2 764 73 52 
Principal investigator: Professor Van den Broucke, 10 Place Cardinal Mercier, Bureau D215 
1348 Louvain-la-Neuve; phone number: +32 (0) 10 479046 
Co-investigator : Alves Jorge, affiliation at IRSS, Clos Chapelle-aux-Champs, 30, Bte B1.30.15 1200 
Bruxelles ; phone number : +32 (0)468367612 
 
Professeur Spinewine is the coordinator of all Di-Prescribe project. PI – Professor Van den Broucke will 
conduct the study according to the GCP and applicable regulations. So, PI will supervise each stage of 
questionnaire validation process, and ensure that the protocol is respected. In addition, PI will provide 
safety updates and periodic progress reports, and he will notify the end of the study and the final study 
report. Under PI's supervision, the co-investigator will develop the different stages for validating the 
questionnaire. Professeur Spinewine and Professeur Van den Broucke will follow and provide feedback 
at each stage of the validation process. A meeting with the whole research team is scheduled every 
month to discuss progress, difficulties and results obtained at each stage of the questionnaire validation 
process. 
 
 
 

Development and validation of a health behaviour theory-based questionnaire to explore the 
willingness of older adults and informal caregivers to deprescribe (HBQtD) 
 
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Version History 
 
Version 
Approval 
Date 
 
Changes  
1  
 
Original 
 
2 
11/08/23 
Amendment  
Anonymity of healthcare professionals included 
in the study and their relationship with the 
sponsor; 
HLS19_Q12 
and 
MHLCS 
questionnaire 
administration  
3 
25/09/23 
Amendment 
Modified Schedule of Activities 
4 
 
Amendment 
 
 
 
 

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2. SIGNATURE PAGE  
 
SPONSOR REPRESENTATIVE  
 
 
 
 
INVESTIGATOR(S)  
 
I agree to conduct this study in accordance with the design and specific provisions of this 
protocol and will only make changes in the protocol after notifying the sponsor. 
 
I understand that I may terminate or suspend enrolment of the study at any time if it becomes 
necessary to protect the best interests of the study subjects.   
 
I agree to personally conduct or supervise this study and to ensure that all associates, colleagues, 
and employees assisting in the conduct of this study are informed about their obligations in 
meeting these commitments. 
 
I will conduct the study in accordance with the protocol, Good Clinical Practice, the Declaration 
of Helsinki, and the moral, ethical and scientific principles that justify medical research.  The 
study will be conducted in accordance with all relevant laws and regulations relating to clinical 
experimentation and the protection of patients. 
 
I will ensure that the requirements relating to Ethics Committee review and approval are met.  
 
I agree to maintain adequate and accurate records and to make those records available for audit 
and inspection in accordance with relevant regulatory requirements including the provision of 
direct access to data and source documents.  
 
I agree to promptly report to the Ethics Committee any changes in the research activity and all 
unanticipated problems involving risks to human subjects or others.  Additionally, I will not 
make any changes in the research without Ethics Committee approval, except where necessary 
to ensure the safety of study participants. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Development and validation of a health behaviour theory-based questionnaire to explore the 
willingness of older adults and informal caregivers to deprescribe (HBQtD) 
 
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3. PROTOCOL SYNOPSIS  
 
Name of Sponsor 
UCLouvain (ARC, Actions de Recherche Concertée – Di-Prescribe) 
Title of Study 
Development and validation of a health behavior theory-based questionnaire to examine 
the willingness of older adults and informal caregivers to deprescribe 
Service(s) in which the experimentation is taking place 
Primary care setting, nursing homes in Brussels and Wallonia 
Publication (reference) 
Studied period :  
September 2023 to october 2024 
Objectives:  
- Primary: to develop and validate a health behavior theory-based questionnaire to examine the 
older adults’ and informal caregivers’ determinants of deprescribing behavior  
- Secondary: assess the psychometric properties of this new instrument 
Hypotheses 
The use of health behavioral constructs in the development of an assessment tool will have 
greater predictive validity than that of existing tools 
Study Design  
Questionnaire development and validation that involve an item development and validation stage 
Number of planned patients:  
- 
345 older adults; 345 informal caregivers  
Main criteria for inclusion (inclusion/exclusion criteria) 
Inclusion criteria: 
Older adult population: 
• Age 60 years or older; 
• Taking at least 5 medications daily; 
• Having at least one chronic condition; 
Informal caregiver (such as spouse, family/ friend caregivers): 
• Self-identified as a caregiver of an older adult who has 60 years old or older, that are 
taking at least 5 medications daily and having one or more chronic condition; 
• The care recipient lived in the community or in a nursing home.  
Exclusion criteria: 
Older adult population: 
• Suffering from psychiatric trouble; 
• Past or present drug or alcohol dependency; 
• Having a terminal illness; 
• Inability to complete a written questionnaire in French due to a functional or cognitive 
impairment; 
• Inability to understand and express oneself in French.  

Development and validation of a health behaviour theory-based questionnaire to explore the 
willingness of older adults and informal caregivers to deprescribe (HBQtD) 
 
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Informal caregiver population: 
• Caregiver age under 18 years old; 
• Caregivers who are paid for the care they provide; 
• Caregiver inability to give consent and complete a written questionnaire in French; 
• Caregiver inability to understand and speak in French. 
Procedures: Schedule of assessments – Study Flowchart 
Statistical Considerations 
Methods that will be used to validate the questionnaire: face validity, content validity, construct 
validity, internal validity and test-retest reliability.  
To assess the psychometric properties of the questionnaire, an exploratory factor analysis (EFA) 
will be performed – construct validity. Face and content validity will be performed by qualitative 
methodology, and using the content validity ratio (CVR). Internal validity will be assessed using 
the Cronbach’s alpha and omega coefficient, and test-retest reliability will be investigated using 
the Cohen’s kappa and Interclass correlation coefficient (ICC). Logistic regression will be 
performed to investigate the association between the determinants and the intention, or 
deprescribing behavior.  
 
 
 

Development and validation of a health behaviour theory-based questionnaire to explore the willingness of older adults and informal caregivers to deprescribe (HBQtD) 
 
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4. SCHEDULE OF ACTIVITIES 
 
Activities/ 
Months 
2023 
2024 
06 
07 
08 
09 
10 
11 
12 
01 
02 
03 
04 
05 
06 
07 
08 
09 
 
 
15d 
15d 
15d 
15d 
15d 
15d 
15d 
15d 
 
 
 
 
 
 
 
 
 
 
 
Questionnaire 
development 
and 
protocol 
redaction 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Ethics 
committee 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Contact 
institutions and 
organizations 
for recruitment 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Cognitive pre-
test with OA 
and IC 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Round 
with 
HCP 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
FG with HCP 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Round with OA 
and IC 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
FG with OA 
and IC 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Recruitment 
for 
questionnaire 
validation 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Results analysis 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Preparing 
publication 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
OA: older adults; IC: informal caregivers; HCP: healthcare professionals; FG: focus group 

Development and validation of a health behaviour theory-based questionnaire to explore the 
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Table of contents 
1. 
TITLE PAGE ................................................................................................................................................................ 2 
2. 
SIGNATURE PAGE ................................................................................................................................................... 5 
3. 
PROTOCOL SYNOPSIS .......................................................................................................................................... 6 
4. 
SCHEDULE OF ACTIVITIES ................................................................................................................................. 8 
5. 
LIST OF ABBREVIATIONS AND DEFINITIONS ......................................................................................... 10 
6. 
ETHICS ....................................................................................................................................................................... 11 
7. 
BIBLIOGRAPHIC REFERENCES ..................................................................................................................... 12 
8. 
RATIONALE ............................................................................................................................................................. 14 
9. 
OBJECTIVES AND GOALS OF THE STUDY .............................................................................................. 14 
STUDY DESIGN AND METHODOLOGY APPLIED............................................................................................. 15 
9.1. 
DESIGN ...............................................................................................................................................15 
9.2. 
DESCRIPTION OF THE POPULATION....................................................................................................19 
9.3. 
STRATEGIES FOR RECRUITING PARTICIPANTS ...................................................................................20 
9.4. 
INCLUSION CRITERIA ..........................................................................................................................21 
9.5. 
EXCLUSION CRITERIA .........................................................................................................................22 
9.6. 
WITHDRAWAL .....................................................................................................................................22 
9.7. 
PROTOCOL DEVIATIONS .....................................................................................................................22 
9.8. 
DATA MANAGEMENT RESPONSIBILITIES ............................................................................................22 
9.9. 
DATA BREACH.....................................................................................................................................23 
9.10. 
DATA ANALYSIS ..................................................................................................................................24 
9.10.1. 
Qualitative Analysis ..................................................................................... 24 
9.10.2. 
Statistical Analysis ....................................................................................... 24 
9.11. 
PROTOCOL AMENDEMENTS ...............................................................................................................26 
10. FINANCE AND INSURANCE.............................................................................................................................. 26 
11. END OF STUDY ...................................................................................................................................................... 27 
12. DISSEMINATION OF RESULTS AND PUBLICATION POLICY ............................................................ 27 
13. ARCHIVING .............................................................................................................................................................. 27 
14. REFERENCES ......................................................................................................................................................... 27 
15. APPENDIX ................................................................................................................................................................. 31 
 
 
 

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5. LIST OF ABBREVIATIONS AND DEFINITIONS 
 
BMQ 
Beliefs about medicines 
BZD 
Benzodiazepines 
CVR 
Content validity ratio 
EFA 
Exploratory factor analysis 
HCP 
Healthcare professionals 
HBM 
Health Belief Model 
HBT 
Health Behavior Theory 
FG 
Focus group 
HL 
Health literacy 
HCP 
Healthcare professionals 
IC 
Informal caregivers 
ICC 
Interclass correlation coefficient 
NH 
Nursing home 
OA 
Older adults 
PATD 
Patient Attitudes Towards Deprescribing 
rPATD 
Revised version Patient Attitudes Towards Deprescribing 
SCT 
Social cognitive theory 
TPB 
Theory of planned behaviour 
TRA 
Protection motivation theory 
TTM 
Trans-Theoretical Model of behaviour change 
WHO 
World Health Organization 
 
 
 

Development and validation of a health behaviour theory-based questionnaire to explore the 
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6. ETHICS 
➢ This protocol, any protocol amendments, informed consent form and other relevant documents 
(eg. recruitment advertisements) will be submitted to the Ethics Committee (EC) for formal 
approval to conduct the study. The decision of the EC concerning the conduct of the study will 
be made in writing to the sponsor. All correspondence with the Ethics Committee will be 
retained in the Investigator File. 
➢ The study will be conducted in accordance with legal and regulatory requirements (Belgian law 
of 7 May 2004, Belgian law for Patient rights 22 August 2002, Private life GDPR 2018), as well 
as the Guidelines for Good Clinical Practice (International Conference on Harmonization 1996), 
and the last version of Declaration of Helsinki (World Medical Association). 
➢ All subjects for this study will be provided a consent form describing this study and providing 
sufficient information for subjects to make an informed decision about their participation in 
this study.  This consent form will be submitted with the protocol for review and approval by 
the EC. The formal consent of a subject, using the EC-approved consent form, will be obtained 
before that subject is submitted to any study procedure. This consent form must be signed by 
the subject or legally acceptable surrogate, and the investigator-designated research 
professional obtaining the consent. The written informed consent document should be 
prepared in the language of the potential patient population. 
➢ The identity of the participant will remain kept confidential according to the General Data 
Protection Regulation of 27 April 2016 (in application on 25 May 2018), to the Belgian law of 
30 July 2018 on the protection of natural persons with regard to the processing of personal 
data and the Belgian patient’s right law (22 August 2002). Personal data will be coded. Subjects 
will not be identified by name or in any other recognizable way in any of the records, results or 
publications related to the experiment. 
 
 
 

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7. BIBLIOGRAPHIC REFERENCES 
 
Prescribing medication is an essential dimension in the care of the older adults (i.e. people aged 
60 or 65 and over, as per World Population Ageing 2019: Highlights (s. d.)), and the 
optimization of drug prescribing, has become an important public health issue, especially for 
the older adults (Spinewine et al., 2007). Even if, polypharmacy (i.e. five or more medications; 
(J. Reeve et al., 2022; Gabauer, 2020), may be appropriate in the treatment and prevention of 
different symptoms or disorders in older adults with multimorbidity (J. Reeve et al., 2022; 
Steinman, 2016; Spinewine et al., 2007), taking multiple medications may also be linked to a 
higher risk of medication-related problems. In fact, the aging process leads to physiological 
changes that can significantly alter both pharmacokinetics and pharmacodynamics (Pazan & 
Wehling, 2021). These age-related physiological changes can increase the risk of adverse drug 
events, and the inappropriate polypharmacy can contribute to drug-drug interaction, lower 
adherence to medication, significant costs to both the patient and the health care system, and 
also decrease the ability of people to perform activities of daily living, due to a functional 
decline, injurious falls, cognitive impairment, among others (O’Donnell & Ibrahim, 2022; 
Gabauer, 2020).  
Therefore, it seems important to reflect, at different levels - micro, meso and macro, on the 
challenges related to the problematic polypharmacy, i.e. “the use of multiple medicines on a 
long-term basis when the intended benefit of the medicines is not achieved, on the potential 
risks outweigh the intended benefits” (J. Reeve et al., 2022). Indeed, this large-scale problem 
was recognized by the World Health Organization (WHO) that launched in March 2017 the 
third Global Patient Safety Challenge with the theme of medication without harm.  
Deprescription, defined by Reeve et al. (2022) as “a planned/ supervised process of dose 
reduction or the stopping of medicines that may be causing harm or conferring no additional 
benefit”, can thus be a strategy, not only in the optimization of drug use in a context of 
polypharmacy, but also a strategy to revert the clinical and economic burden of polypharmacy  
(Reeve et al., 2022; Roux et al., 2022). 
In reality, a systematic review and meta-analyses realized by Page et al. (2016), emphasized 
that this process of deprescribing to reduce polypharmacy is, not only feasible, but also safe. In 
addition, deprescribing seems to have some health benefits, and there are a trend to decrease 
mortality in the 65-80 years-old age group (Page et al., 2016).   
Therefore, in this process of de-prescription, the patient, and even the informal caregivers, 
should have an active role in the health decisions that concern themselves (Chock et al., 2021; 
Baumgartner et al., 2020). Deprescription requires, in this way, a person-centered approach, 
with a shared decision-making process, and according to E. Reeve et al. (2018), some older 
patients are willing to be involved in this decision making process.  
However, physicians report some patient reluctance or unwillingness to deprescribe, which is 
a very significant barrier to implementing deprescribing in clinical practice (E. Reeve et al., 
2018). In fact, according to Parker et al. (2022), taking into account the patient and his impact 
in deprescribing, is an essential factor to understand and thus increase the effectiveness of 
interventions to reduce low-value care.   
Therefore, as implementation deprescribing requires a complexes changes to established patters 
of behaviors (Scott et al., 2021), understanding the cognitive mechanisms underlying patient’s 
and caregiver’s behavior with respect to deprescribing, seems essential to improve the 

Development and validation of a health behaviour theory-based questionnaire to explore the 
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collaborative work between the patient, or even the caregivers, and the health professionals, to 
achieve the best health outcomes for the patient (Parker et al., 2022; E. Reeve et al., 2013). 
In reality, HBT provides a series of concepts deriving from social, cognitive and motivational 
psychology, that can be useful in understanding why people behave in certain ways in relation 
to their health (Gehlert & Ward, 2019). The most well-known and often-used theories are the 
Health belief Model (HBM; (Godin, 1991), the Theory of Planned Behavior (TPB; (Ajzen, 
1991), as an extension of the Theory of Reasoned Action (TRA; (Ajzen & Madden, 1986), and 
the Protection Motivation theory (PMT; (Rogers, 1975). One major limitation of these models 
is that they actually "predict" behavioral intention, but they do not inform how to change health 
behaviors (Parker et al., 2022; Bandura, 2004, Godin, 1991).  
Consequently, Bandura (2004) proposes a causal model, the Social Cognitive Theory (SCT), 
that “offers both predictors and principles on how inform, enable, guide, and motivate people 
to adapt habits that promote health and reduce those that impair it”. According to this theory, 
“behavior, cognitive and other personal factors, and environmental events all operate as 
interacting determinants that influences each other bidirectionally” (Bandura, 1988).  
Moreover, given that behavior change involves processes that take place over time, the Trans-
Theoretical Model of change (TTM; (Prochaska & DiClemente, 1983)) posits that health 
behavior change is a process that involves progression through a series of six stages of change: 
precontemplation, contemplation, preparation, action, maintenance, and termination 
(Prochaska & Velicer, 1997). 
It is also interesting to note in Reeve et al.’s (2013) systematic review, that despite patients' 
ability to understand the risks and benefits associated with a certain behavior, especially about 
drug therapy, they showed limited ability to translate this information into decisions about 
whether or not the therapy is appropriate. This finding is even more striking among the elderly 
who often have a lack of knowledge about drug treatment and poor understanding of treatment 
aims, which consequently can be reflected in the inappropriate use of medicines (Parekh et al., 
2018). Therefore, these elements refer to Health Literacy (HL), that can be defined as “the 
degree to which individuals have the capacity to obtain, process and understand basic health 
information and services needed to make appropriate health decisions” (Nielsen-Bohlman et 
al., 2004 cit by Parekh et al., 2018), and that may be an important covariant to consider in the 
context of deprescription.  
 
Screening Tools 
In clinical practice, the existence of screening tools can be very useful, in this case to identify 
patients who will be more likely to respond well to therapeutic deprescription interventions 
(Turner et al., 2020). In reality, several tools have been developed and used, particularly in the 
identification of inappropriate drug use in the older patients, such as The Beers criteria (Beers, 
1997) and Medication Appropriateness Index (Hanlon & Schmader, 2022). However, and 
despite its wide use, these tools do not provide guidance on how to stop inappropriate 
medication (E. Reeve, Shakib, et al., 2013).  
In addition, the success of therapeutic deprescription will depend not only on medical factors, 
but also on patient factors. Therefore, being able to explore and objectively capture patients' 
beliefs and attitudes towards this therapeutic strategy seems essential (E. Reeve, Shakib, et al., 
2013). Thus, other tools have been developed, including The patients’ attitudes towards 
deprescribing (PATD) questionnaire, and its revised version questionnaire (rPATD; (E. Reeve 

Development and validation of a health behaviour theory-based questionnaire to explore the 
willingness of older adults and informal caregivers to deprescribe (HBQtD) 
 
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et al., 2016)), and Beliefs about Medicines Questionnaire (specific section) (BMQ-Specific) 
(Horne et al., 1999). 
However, according to Turner et al. (2020) analyses, all 25 items found in the rPATD and 
BMQ-specific screening, only 8 were associated with deprescribing outcomes. In addition, 
these tools presents a low predictability validity for successful deprescribing (Chock et al., 
2021; Turner et al., 2020), and an important gap between participants’ intention and 
deprescribing behavior was also identified by Turner et al. (2020), with 86% of participants that 
are willing to deprescribe, but only 41% of participants successfully deprescribing their 
prescription. This significant gap and low predictive validity, can be explained by the fact that 
PATD and revised version was developed without a behavioral theory as a theoretical basis, 
whereas attitudes are a construct present in models of health behavior, such as the TPB (Ajzen 
& Madden, 1986). As a result, this questionnaire as well as the BMQ-specific questionnaires, 
do not take into account different critical domains that can be relevant to deprescribing, such as 
self-efficacy beliefs, outcome expectations, subjective norms, health goals, environmental 
barriers and enablers, among others (Linsky et al., 2015).  
8. RATIONALE  
The studied population in this study is twofold: older adults and informal caregivers.  
Older adults 
This study has a focus on particular population - older adult population. Advances in medicine 
have led to an increase in life expectancy, and a worldwide rise in the number of older people. 
As a result, several problems have also accompanied this increase, such as the growing number 
of chronic diseases and related polypharmacy, resulting in a significant burden not only for the 
older person, but also for healthcare systems (Pazan & Wehling, 2021). 
 
Informal caregivers 
In addition, the aging process can bring about different changes and disabilities in sensory, 
cognitive and physical functions, which may lead some older people to choose to involve family 
members or close friends in managing their health (Wolff & Boyd, 2015).  
 
Hypothesis 
According to Chock et al. (2021) and  Turner et al. (2020) current tools, such as the BMQ and 
the widely used rPATD, have a number of limitations, particularly in terms of predictability 
validity for successful deprescribing. In addition, the rPATD items were developed without any 
theoretical basis in health behaviors, whereas attitudes are an important concept found, in 
particular, in the TPB (Ajzen & Madden, 1986). As a result, we hypothesis that the use of health 
behavioral constructs in the development of an assessment tool will have greater predictability 
validity on deprescribing behavior than that of existing tools.  
9. OBJECTIVES AND GOALS OF THE STUDY 
Primary objective: 

Development and validation of a health behaviour theory-based questionnaire to explore the 
willingness of older adults and informal caregivers to deprescribe (HBQtD) 
 
Protocol II– dated on 2023/08/11 
 
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To develop and validate a health behavior theory-based questionnaire to examine the older 
adults’ and informal caregivers’ determinants of deprescribing intention or behavior (with 
separate version for older adult and informal caregiver). 
Secondary objectives: 
• Establish the face and content validity of the questionnaire; 
• Assess the psychometric properties of this new tool, by performing an exploratory factor 
analysis (EFA). 
Expected benefits of the research 
Despite the many benefits of taking medication, multimorbidity and the chronicity of certain 
health problems lead to multi-medication intake, which can entail major risks for the older 
people. Thus, deprescribing is an important dimension in the care of the older adults, and this 
study intends to provide a new instrument, developed on the basis of constructs from behavioral 
health theories, which is expected to be more accurate than those currently in use. This tool will 
thus be able to provide more information about the older adults’ and their caregivers’ views 
about deprescribing and also the socio-cognitive factors that can impact their willingness to 
engage in deprescribing behavior. Consequently, this information could be useful in the 
development of interventions aimed at medication deprescribing, with a patient-centered or 
family-centered deprescribing approach. 
STUDY DESIGN AND METHODOLOGY APPLIED 
9.1. Design 
Type of study 
Questionnaire development and validation – older adult and informal caregiver version 
 
Study configuration 
The initial questionnaire was developed considering the results of a previous systematic review 
(article currently being written), which was intended to identify (concepts included in) 
behavioral health theories (HBTs) that explain older adults' and informal caregivers' 
deprescribing intention and/or their actual deprescribing behavior. This systematic review, 
reveled several main dimensions, such as goals intention to deprescribe, perceived risks about 
medication, self-efficacy towards deprescribing, subjective norms, social support to 
deprescribe, and finally opportunities for deprescribing. This systematic review, also showed 
that attitudes was already widely investigated, indeed four systematic reviews and two meta-
analysis were already performed, synthesizing studies that have used PATD and the revised 
version (Seewoodharry et al., 2022; Oktora et al., 2022; Chock et al., 2021; Weir et al., 2021).  
As a result, the items of this initial questionnaire were developed according to the dimensions 
found in the systematic review, the main results of the systematic review focused on the rPATD 
and the Beliefs about Medicines questionnaire (BMQ), since a predictor of risk perception was 
beliefs about medication (Martin et al., 2013).  
The initial version for informal caregivers was developed by modifying the wording of the 
items, in the version for the older adults, adapting them for informal caregivers.  

Development and validation of a health behaviour theory-based questionnaire to explore the 
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Another two questionnaires will be used in this study: one that measure health literacy 
(HLS19_Q12; (Pelikan et al., 2022)) and another one that assess the locus of control (MHLC; 
(Wallston et al., 1978)). The previous systematic review reveled that the HL was positively 
associated with the willingness to deprescribe (Gillespie et al., 2019). The HLS19_Q12 is thus 
the questionnaire that will be used in this study. This instrument was built on the conceptual 
framework and definition of comprehensive, general HL developed in the HLS_EU (Pelikan et 
al., 2022). Indeed, the concept-based in the development of HLS_EU  refers to “… people’s 
knowledge, motivation, and competencies to access, understand, appraise and apply 
information to form judgements and take decisions in terms of healthcare, disease prevention 
and health promotion to improve quality of life during the life course” (Sørensen K et al., 2012 
cit by (Pelikan et al., 2022).  
In addition, the locus of control was also identified in one study, in the previous systematic 
review, as having an impact on deprescribing behavior (Elsesser & Sartory, 1998). As a result, 
the Multidimensional Health locus of control scale (MHLC; (Wallston et al., 1978)) will be 
used. According to Lachman (1986) the multidimensional measurement is desirable for the 
older people, because “it allows for the possibility of differential change trajectories across 
dimensions” (Gurin & Brim, 1084 cit by Lachman, 1986), as in the aging process older people 
may become more sensitive to the external power or chance, but without changing one’s sense 
of internal control (Lachman, 1986).  
 
Study design 
The development and validation of the questionnaire comprise 4 steps: 
1. Item Development process  
The conceptualization of the concepts used in the questionnaire was based on the results of the 
systematic review carried out previously. The items were built in relation to the most relevant 
constructs and predictors identified in the results of the systematic review, and some items from 
two different questionnaires (rPATD and BMQ) were also used to assess the components of 
some constructs, such as attitudes and perceived risk. The dimensions importance, in a first step 
were identified by discussion with the promotor in relation to the systematic review results. The 
questionnaire and items format were also discussed with the promotor, and a statistician from 
SMCS.  
Some considerations have been taken into account in the item construction: “Statements should 
be simple and short as possible, and the language used should be familiar to target 
respondents… Items should address only a single issue… Leading questions should be avoided, 
as they may bias responses. Items that all respondents would answer similarly should not be 
used, as they will generate little variance” (Hinkin, 1998). In addition, items related to 
deprescribing behavior were regrouped and separated from those related to medication use.  
 
2. Preliminary pilot testing  
All piloting process will follow an iterative approach, allowing adjustments to be made 
throughout the exchanges between the various stakeholders involved in this process. 
a. Prior to the pre-test, the questionnaire will be distributed to 5 colleagues on the 
research team to check all the initial items and adjust them, if necessary.  
b. Then, “cognitive pre-test” will be performed with 5 older adults and 5 informal 
caregivers to check the linguistic and analytical construction of the items, through respondent 

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understanding of the items in the questionnaire. This first test will be performed by qualitative 
methodology, more precisely structured interviews. Respondents will be encouraged to express 
their thinking aloud when answering each item. After this first test, items that caused 
comprehension problems will be discussed with the research team and then they will be adjusted 
or eliminated. The results of this first test lead to a first draft of the questionnaire to the older 
adults and to the informal caregivers.  
c. In the following step, the item development and questionnaire validation will 
include a first round with healthcare professionals, and a second round with older adults and 
informal caregivers. This phase will assess the face and content validity. Different techniques 
can be used to assess content validity, but in this study we will use the one proposed by Lawshe 
(1975), the Content validity ratio (CVR), once it has also been used in other studies such as for 
the validation of the rPATD (E. Reeve et al., 2016).  
i. Healthcare professionals 
According to the principle of purposive sampling, 8 health professionals: 2 geriatricians, 2 
general practitioners (GP), 2 pharmacists, and 2 nurses, will be enrolled in this study to rate on 
a Likert-scale the appropriateness of having each item in the questionnaire.  
For improving the questionnaire, participants will also be encouraged to make comments and 
suggestions.  
One focus group (FG) will be then organized to discuss the results from this second test, and a 
second draft can be developed, after discussing the results with the research team and before 
offering it to older adults and their informal caregivers. 
As regards the FG, it's essentially a small group of people, between 6 and 16, who come together 
to discuss a particular and common subject (Kohn & Christiaens, 2012). Consequently, one 
group with health care professionals will be composed of at least 6 participants who have 
showed an interest in participating in the discussion (question at the end of the questionnaire). 
The focus group will be moderated by the co-investigator and will take place at a location to be 
agreed with the participants. 
ii. Older adults and informal caregivers  
As for the healthcare professionals, a convenience sample of 10 older adults, and 10 informal 
caregivers, will be asked to provide individual feedback on the questionnaire items. One FG, 
with older adults and informal caregivers will be organized to discuss the results of the self-
administered questionnaire. The group will be composed of at least 6 participants (3 older adults 
and 3 informal caregivers) who have shown an interest in participating in the discussion 
(question at the end of the questionnaire). A third version of the questionnaire will be obtained 
after discussion the results with research team.  
 
3. Pre-test of the questionnaire – older adult and informal caregiver version 
Once the final version of the questionnaire developed, it will be administered to a small group 
of participants, generally 10% of the sample size required to perform an EFA (Aithal & Aithal, 
2020). It will be asked to the older adults and to the informal caregivers to complete the 
questionnaire and to provide any comments about the way items have been written and on items 
comprehension. This pilot study will help to assess the clarity of the items and to remove 
irrelevant items.  
In this validation step will also be administered the HLS19_Q12 and MHLCS. 
 

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4. Validation of the questionnaire – older adult and informal caregiver version  
The final item selection process will incorporate the results of the different qualitative analyses 
(interviews and FG) and quantitative analyses of the field trial data. This final version of the 
questionnaire will be then applied to a large sample size of older adults and informal caregiver 
for reliability validation.  
This validity process “… refers to the degree to which evidence and theory support the 
interpretations of test scores for proposed uses of a test. Validity is, therefore, the most 
fundamental consideration in developing and evaluating tests” (AERA, APA, & NCME, 2014 
cit by Clark & Watson, 2019). As a result, during this phase, a construct validity will be carried 
out, which is related to the “evaluation of the extent to which a measure assesses the construct 
it is deemed to measure” (Strauss & Smith, 2009). The internal consistency will be also 
calculated, as it reflects “the extent to which the questionnaire items are inter-correlated, or 
whether they are consistent in measurement of the same construct” (Tsang et al., 2017). Finally, 
a test-retest reliability will be performed, by repeating the administration of the same 
questionnaire with a small sample of participants (20 older adults and 20 informal caregivers) 
who have already completed the questionnaire. This process will ensure the consistency of 
questionnaire items responses across repeated administration (Tsang et al., 2017). 
The two additional questionnaires (HLS19_Q12 and MHLCS) will be administered to all 
participants (older adults and informal caregivers) in this final stage of the questionnaire 
validation process.  
 
Expected duration of subject participation 
Participants will be included throughout the questionnaire development and validation process, 
which will begin as soon as the ethics committee's opinion is received, and will continue until 
the sample size required for validation of the questionnaire is reached, in the final phase. The 
whole process is expected to take around 12 months.  
 
Planned timetable 
Activities/ 
Months 
2023 
2024 
06 
07 
08 
09 
10 
11 
12 
01 
02 
03 
04 
05 
06 
07 
 
 
 
15d 
15d 
15d 
15d 
15d 
15d 
15d 
 
 
 
 
 
 
 
Questionnaire 
development 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Ethics 
committee 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Cognitive pre-
test with OA 
and IC 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Round 
with 
HCP 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
FG with HCP 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Round 
with 
OA and IC 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
FG with OA 
and IC 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Questionnaire 
validation  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
HCP: Healthcare professionals; FG: focus group; OA: older adults; IC: informal caregivers  
 

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Method for data collection 
The questionnaire begins with a short introduction covering the importance of the study, its 
objectives, anonymity and the non-obligation to participate in the study and withdraw if desired. 
Consent will be signed before starting to fill in the questionnaire. The questionnaire initially 
asks 3 questions to determine participant eligibility, and the initial draft of the questionnaire 
consists of 3 main parts: 
1. First section with questions relating to the socio-demographic and clinical 
characteristics of the participants. There are 5 basic demographic questions related to 
age, sex, education, relationship status, residence (at home, NH, …). Three additional 
questions are included in this section to: (1) assess how the person feels about his or her 
health or that of the care recipient, on a Likert scale ranging from 1 “Poor” to 5 
“Excellent”; (2) to know how many different medications (including those not 
prescribed by the doctor) the older person/care recipient takes per day; (3) to know if 
the person or the care recipient has ever tried, in the past, to reduce or stop some of the 
drugs in their usual treatment; (4) to know if the person/ informal caregiver are willing 
to deprescribe; (5) to know if the person/ care recipient is currently in the process of 
deprescribing at least one of the medication he or she is currently taking.  
2. Second section with 58 questions for older adult questionnaire version and 55 questions 
for the informal caregiver version on factors that may be potential obstacles or 
facilitators to deprescribing behavior. Each item is rate on a Likert scale going from 1 
“strongly disagree” to 5 “strongly agree”. 
9.2. Third section with 3 open-ended questions for participants to comment on 
the questionnaire format, factors that have not been addressed and items 
that may not be relevant. An additional question is added to this first draft to 
identify participants interested in participating in the FG.Description of the 
population 
Older Adult population  
• Be at least 60 years old : different ways of defining the older people exist, but in 
statistical terms, the older people are often classified above a certain age threshold (European 
Commission. Statistical Office of the European Union., 2020). For the purposes of this study, 
we adopt the definition given by the United Nations in its report called World Population 
Ageing 2019: Highlights (s. d.), that older people are those aged 60 or 65 years or older.  
• Take 5 or more medications daily: the ageing process is often accompanied by an 
increasing burden of chronic illness, and consequently by chronic medication use that can lead 
to polypharmacy, defined as taking 5 or more medications (Nordin Olsson et al., 2011). In turn, 
polypharmacy can be considered as the most obvious sign of risks in medication treatment 
(Nordin Olsson et al., 2011), and potentially inappropriate medication (PIM) that include 
medication and medication combination, should be avoided in this population due the higher 
risk of causing more harm than benefit for the user, in particular, an increase mortality (Muhlack 
et al., 2017).  
Informal caregivers 

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• Spouse, family member or closer friend: in this study informal caregiver refers to a 
family member, a friend that provide care or support to a dependent older person with physical 
or cognitive functions declines. The relationship between the informal caregiver and the care 
recipient is based on solidarity, and so “based on mutual help and moral obligation within 
families and social networks. Informal caregivers’ work can be unpaid or remunerated” in 
some way” (Abouzaid et al., 2014). Therefore, in this study those who provided informal care 
are: (a) working-age adults who care for older parents with disabilities, family members, 
neighbors or friends; (b) people of retirement age or older who care for their partner, family 
members, neighbors or friends 
In addition, the role of the informal caregiver may vary depending on the older person's 
disability, but also according to their own characteristics. However, in the ambulatory setting, 
medication management has been identified as one of the most important informal caregivers’ 
role, and good medication management “contributes to improve health outcomes and reduce 
institutionalizations for the care recipient” (Gillespie et al., 2014). As a result, informal 
caregivers should be involved in the deprescribing decision and process (E. Reeve et al., 2016).  
 
Number of participants expected  
Healthcare professionals 
n=8 
Questionnaire self-administration: 2 geriatricians, 2 
GP, 2 pharmacists, and 2 nurses 
Older Adults  
n=345 
Cognitive 
pre-test: 
n=5 
Questionnaire 
self-
administration: 
n=10 
Pre-test: 
n= 30 
Validation: 
n=300 
Informal caregivers  
n=345 
 
Cognitive 
pre-test: 
n=5 
Questionnaire 
self-
administration: 
n=10 
Pre-test: 
n= 30 
Validation: 
n=300 
 
9.3. Strategies for recruiting participants 
Health care professionals 
For the recruitment of healthcare professionals, several organizations will be contacted, more 
specifically: 
• General practitioners: « Centre académique de médecine général » - CAMG; ASBL 
« Collège de Médecine Générale de Belgique francophone » ; 
• Specialist physician: Belgian Young geriatricians – BYG and the Belgian Society of 
gerontology and geriatrics – BSGG; 
• Pharmacists: “Centre académique de soins pharmaceutiques » - CASP and the Belgian 
pharmaceutical association – APB 

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• Nurses: convenience recruitment through contact with a number of nursing home and 
homecare associations.  
Different recruitment channels are envisaged to ensure that the healthcare professionals who 
will be recruited have no relationship with the researcher and/or the sponsor of this study. 
Older adults  
Initially, convenience recruitment will be carried out for the “cognitive pre-test”, and for the 
questionnaire self-administration and FG. The French-speaking federation of patient and family 
associations- LUSS, and ASBL “Aidants proches”, will be contacted to help recruit 
participants. Then, older adults in ambulatory setting will be recruited through community 
pharmacies and GP. Contacts will be made with a large number of community pharmacies and 
also with GP in private practice and in "Maison Médicale" practices, in Brussels and Wallonia. 
Eligible patients will receive from pharmacists and GPs an envelope containing the information 
form, consent form and questionnaire, as well as a stamped envelope for returning the 
questionnaire and signed consent form. 
In addition, day centers for older adults will be contacted, as well as organizations and social-
health services and “Résidence Service”. For Brussels, Iriscare provides a list of available day 
centers, and senior.irisnet provides a list of homecare organizations. For Wallonia, AVIC 
provides a list of day centers to contact, as well as a list with homecare organizations. For the 
older adults who are eligible and agree to participate, a member of staff or the researcher will 
inform residents about the study, request the signature of informed consent and, if necessary, 
help in completing the questionnaire. For participants who are unable to take part, their informal 
caregivers will be asked if they are willing to participate (informal caregiver version of the 
questionnaire). 
For the NH participants, a convenience sample of NH, in Brussels and Wallonia, will be 
contacted for participation. As for the day-care centers, the researcher or a NH staff member 
will inform residents about the study, request the assignment of consent and, if necessary, help 
in completing the questionnaire.  
Informal Caregivers: 
As with the recruitment of seniors, LUSS and ASBL “Aidants proches” will be contacted to 
help recruit participants. Pharmacists and GPs will also be informed of the informal caregiver 
version of the questionnaire, and if eligible, will give to the caregiver an envelope with 
information form, the consent form, and the questionnaire (informal caregiver version) together 
with a stamped envelope to return the questionnaire and the signed consent form.  
For residents in NH, or in a day-care center, or for those at home but unable to fill in the 
questionnaire and who have a close caregiver, the staff member of the different teams will 
provide the information and give all the necessary documents, as well as the questionnaire, to 
the close caregivers who agree to take part in the study. 
9.4. Inclusion criteria 
Older adult participants will be eligible for this study if they satisfied the following criteria: 
• Age 60 years or older; 
• Taking at least 5 medications daily; 
• Having at least one chronic condition.   
Informal caregiver participants will be eligible for this study if: 

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• They self-identified as a caregiver (defined as having any role in a family member or 
friend’s management of health and/ or medication management) of an older adult who 
has 60 years old or older, that are taking at least 5 medications daily; 
• The care recipient lived in the community (at home with or without the caregiver) or in 
a NH.  
9.5. Exclusion criteria 
Older adult participants will be excluded from this study if they meet any of the following 
criteria: 
• Suffering from psychiatric trouble; 
• Past or present drug or alcohol dependency; 
• Having a terminal illness; 
• Inability to complete a written questionnaire in French due to a functional or cognitive 
impairment; 
• Inability to understand and express oneself in French.  
Informal caregiver participant will be excluded from this study if they meet any of the following 
criteria: 
• Caregiver age under 18 years old; 
• Caregivers who are paid for the care they provide; 
• Caregiver inability to give consent and complete a written questionnaire in French; 
• Caregiver inability to understand and speak in French.  
9.6. Withdrawal 
Not applicable 
9.7. Protocol Deviations 
Any significant deviations from the study inclusion or exclusion criteria, study conduct, patient 
management or evaluation will be described and justified in the final report and communicated 
to the Ethics Committee, as appropriate. 
9.8. Data Management Responsibilities 
The questionnaire for the older adults will be either a paper version for self-administration, or 
completed with the help of the researcher or a member of the NH or day-care center staff. 
However, considering the growing development of IT tools for all age categories, and despite 
the fact that the older people are slower in adopting new technologies compared with the young, 
there is a proportion of this population that uses new information and communication 
technologies (Yap et al., 2022). So, a questionnaire will also be available online, and distributed 
through older adults’ association above for recruitment purposes, and personal or professional 
networks, in Belgium.  
The questionnaire for informal caregivers will also have both a paper and an online version, 
distributed by the caregiver associations and also by personal or professional networks, in 
Belgium.  

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Both versions of the questionnaire will be distributed using Qualtrics (UCL license) - a cloud-
based platform for creating and distributing web-based surveys.  
9.9. Data breach 
Before taking part in this study, participants will be informed how, by whom and for which 
purpose they are being asked to be involved. This information will be given in writing in an 
information sheet together with the consent form (Appendix). 
Qualitative methodology 
For the first qualitative phase of the questionnaire's development, anonymity of all participants 
(healthcare professionals, older adults and informal caregivers) will be ensured by assigning an 
identifier code when analyzing comments from the questionnaire's self-administration and 
when transcribing and analyzing the FG. Also, to ensure that participants are not identified, but 
to be able to re-contact them, in particular for FG planning, any information likely to reveal the 
identity of participants (names) will be put in a separate document, secured by a password and 
stored offline on the hard. The questionnaires’ comments and transcribed FG will also be stored 
offline and password-protected for 20 years at the ‘Service des Archives’ from the UCLouvain.. 
This procedure will be also explained to the participants, written and orally.  
 
Quantitative methodology  
In the quantitative phase of questionnaire validation (older adult and caregiver version), 
participants (older adults and informal caregivers) will be informed in writing, via an 
information sheet attached to the consent form, of how, by whom and for what purpose they 
are being asked to participate. In addition, in specific settings: ambulatory setting – day-care 
and home care and in NH setting, the information will also be communicated orally to the older 
adults, together with the information sheet and the consent form. It will be explained orally and 
in writing that participants will be free to choose whether or not to take part in the study, with 
no implications for the quality of care they receive, or for the relationship between patient/ 
informal caregiver and healthcare professional. They will also be free to withdraw from the 
study at any time without justification.  
For those who agree to participate, anonymity will be ensured by the allocation of an identifier 
code. All information likely to identify participants, such as name, date of birth or address, will 
not be requested. In this study, general information, such as age category, gender, place of 
residence (at home, accompanied or alone, in a NH), marital status and level of education will 
be requested. 
In this study, participants will not be asked about sensitive information concerning the health 
of the older adult, or about information contained in patient records (e.g. biometric data, hospital 
information, medical photographs, biological traits, genetical material, among other sensitive 
information), and no patient records will be consulted. Other types of sensitive information, 
such as those revealing racial or ethnic origin, political opinions, religious or philosophical 
beliefs, trade-union membership, sexual orientation or activity will not be investigated. This 
study will focus on questions relating to the number of medications taken by the person or care 
recipient, as well as their perception of their (or the care recipient's) health status, medication 
deprescription and medication intake. All the data to be collected are based on a theoretical 

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framework derived from a systematic literature review, and are aimed at being adequate and 
relevant to the development and validation of the questionnaire. 
Qualtrics is a secure web application that will be use to encoded paper questionnaires, and also 
for data capture from the online questionnaires. Only the users that need to access the data (the 
research team) will be allowed to do so, and paper questionnaires will be destroyed once they 
have been transcribed into Qualtrics. 
No data transfer is planned in this study, either within or outside the European Union.  
In the event of unintended disclosure of data, no negative effects are expected for participants. 
In addition, any protocol breaches will be immediately (within 7 days) reported by the 
investigator, in accordance with the investigators, to the Ethical Committee.  
The Sponsor or designee must report to ethics committee, serious data breaches : transgressions 
against the study protocol or the regulation that are likely to significantly affect the safety and 
rights of a subject or the reliability and robustness of the data generated in the study. 
9.10. Data Analysis 
9.10.1. 
Qualitative Analysis 
 
In the early stages of questionnaire development and validation – face and content validity, it 
seemed appropriate to seek the opinions and comments of healthcare professionals with 
expertise in the care of the older people and who are aware of the problem of polypharmacy 
and the importance of medication deprescription, as well as our target population – older adults 
and informal caregivers. In this respect, a qualitative methodology is appropriate for 
understanding the needs of users and care providers (Kohn & Christiaens, 2012). For the data 
analysis, the open-ended questionnaire responses concerning comments will be analyzed for 
common or contradictory information, which will be used to construct the guide for the FG. 
Full transcriptions of the FGs will be performed and an analysis of the corpus will be carried 
out by deductively identifying the units of analysis, which will be used for adjusting or 
eliminating items from the questionnaire.  
 
9.10.2. 
 Statistical Analysis 
To assess the psychometric properties of the questionnaire, an EFA will be performed. The aim 
of this study is to develop and validate a new measurement instrument, which is why we will 
use an exploratory method, as no a priori structure is known about the linear relationships 
between items and factors. (McCoach et al., 2013). Thus, using the EFA it will be possible to 
reduce data by exploring  “… the dimensionality of an instrument by finding the smallest 
number of interpretable factors needed to explain the correlations among set of items” 
(McCoach et al., 2013).  
Sample Size 
According to Yong & Pearce (2013), EFA performs better with a larger sample size, as it reduce 
the error in the data. However, no formal sample size calculation is available for EFA, some 
authors recommend at least 200 participants (McCoach et al., 2013), while others put the 
targeted figure at 300 (Yong & Pearce, 2013). So, in this study, we are targeting a sample of 
300 older adults and 300 informal caregivers. For the test-retest reliability, a sample size of 20 

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older adults, and 20 informal caregivers will be selected, as was used for rPATD validation (E. 
Reeve et al., 2016) and rPATD version for BZD (Pétein et al., 2023). 
As described earlier, this study will include an heterogeneous sample (recruitment will be 
carried out in various structures in Brussels and Wallonia ) to minimize the influence of 
variance and factor loading, which “give us an idea about how much the variable has 
contributed to the factor… they represent the strength of the correlation between the variable 
and the factor” (Kline, 1994 cit by Yong & Pearce, 2013).  
Psychometric proprieties of the questionnaire  
The appropriateness of the data factor analysis, considered “to be a variable describing how 
much an individual would score on a factor” (Yong & Pearce, 2013), will be assessed using 
the Kaiser-Meyers-Olkin test and Bartlett’s test of sphericity. Factors will be extracted using 
the Principal Axis Factoring, that is based on the notion “that all variables belong to the first 
group and when the factor is extracted, a residual matrix is calculated. Factors are then 
extracted successively until there is a large enough of variance accounted for in the correlation 
matrix” (Tucker & MacCallum, 1997 cit by Yong & Pearce, 2013). In addition, for a better 
interpretation of the factors, a rotation will be performed, more precisely an oblique rotation 
(Yong & Pearce, 2013). The number of factors to be retained will be determined using the 
Kaiser-Guttman criterion (retaining all factors that are above the eigenvalue of 1) and the scree 
test (retaining all factors that are above the point of inflexion in the scree plot). Loadings above 
0.30 will be considered as significant, as “anything lower would suggest a really weak 
relationship between the variables” (Tabachnic & Fidell, 2007 cit by Yong & Pearce, 2013).  
Another essential step in the creation of a questionnaire is to gather evidence of the score's 
reliability (E. Reeve et al., 2016). In reality, score reliability “is an indication of the consistency, 
stability, or precision of scores” (McCoach et al., 2013). Consequently, reliability focus on two 
types of measurement: internal consistency that estimate a “measurement error within the set 
of questions” (McCoach et al., 2013) and test-retest reliability estimates, that is a measurement 
error across two or more instrument administration (McCoach et al., 2013).  
The most commonly used estimated of internal consistency is Cronbach’s coefficient alpha (α; 
(McCoach et al., 2013)). Nevertheless, α is predicted on several assumptions, that are not 
always respected (Trizano-Hermosilla & Alvarado, 2016; McCoach et al., 2013), which is why 
the omega coefficient (ω; (McDonald, 1999)) will also be used, as an alternative to α (Doval, 
2023; Trizano-Hermosilla & Alvarado, 2016). In reality, a number of researchers showed that 
ω is a more sensible index, with lower risk of over- or underestimating reliability (Dunn et al., 
2014). Therefore, the reliability coefficient range between 0 and 1, and a value above 0.7 will 
be considered as good internal consistency, while a value above 0.90 will be considered as 
excellent (Koo & Li, 2016). 
According to Koo & Li (2016) “A more desirable measure of reliability should reflect both 
degree of correlation and agreement between measurements”, that’s why the intraclass 
correlation coefficient (ICC) will be used to evaluate test-retest reliability at the factor level, 
and linear-weighted Cohen’s Kappa and percent agreement at the individual item level. These 
measurements have been used to validate other instruments such as rPATD (E. Reeve et al., 
2016) and the rPATD version for BZDs (Pétein et al., 2023). The ICC classified the reliability 

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as poor (<0.50), moderate (0.50-0.75), good (0.75-0.90) and excellent (>0.90) (Koo & Li, 
2016). The Cohen’s Kappa nomenclature classify the strength of agreement also as poor 
(<0.00), slight (0.00-0.20), fair (0.21-0.40), moderate (0.41-0.60), substantial (0.61-0.80) and 
almost perfect (0.81-1.00) (Landis & Koch, 1977).  
All numerical variables will be described using means, medians and standard deviation, 
whereas all categorical variables will be described using frequencies and proportion. A logistic 
regression analysis will be performed to better understand the association of items from the 
questionnaire and intention, or actual deprescribing behavior. The moderating influence of HL 
and locus of control on the effect of the determinants on deprescribing intention or behavior 
will be checked via moderation analysis using bootstrapping. Statistical analysis will be 
conducted using SPSS Statistics version 1.0.0.1406, and a type I error rate of <0.05 will be 
considered significant.  
9.11. Protocol Amendements  
If amendments to the protocol (modifying sense or objectives or modifying the study 
procedures) turn out to be necessary, they will be subjected at first opinion of the promoter of 
the study. After agreement by the promoter, these amendments will then be submitted to the 
opinion of the Ethic Committee having examined the initial protocol. 
10. 
FINANCE AND INSURANCE 
This study is part of WP2 of the Di-Prescribe project, with ARC funding.  
As part of this project, a budget has been set aside for stakeholder involvement. As it is planned 
to carry out FG with healthcare professionals, older adults and informal caregivers, a 
compensation of 50€ per person and per meeting will be granted. The budget also includes a 
travel allowance for participants. In addition to the involvement of stakeholders, a cost will be 
incurred for the purchase of stamps and envelopes for the return of paper questionnaires. This 
cost will be covered by the budget allocated for this purpose by ARC project.  
 
The experimentation is covered under the Belgian Law of May 7, 2004 by a no-fault 
insurance (type of coverage: liability insurance). 
Policy holder: 
UCLouvain 
Place de l’Université 1 
1348 Louvain-la-Neuve 
 
Issuer of the certificate of insurance: 
MS Amlin Insurance SE  
Boulevard du Roi Albert II, 37 
1030 Brussels 
N° de police : LXX111372 
 

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11. 
END OF STUDY 
The study end date is the date of the last returned questionnaire, which will be required to 
reach the sample size estimation. A maximum of one year is planned to complete this study, 
including recruitment, data collection, data analysis and preparation of the publication.  
12. 
DISSEMINATION OF RESULTS AND PUBLICATION POLICY 
The progress and results of this study will be discussed with the Di-Prescribe research team. 
The protocol and final results will be presented at seminars scheduled as part of the doctoral 
program. At the end of the study, a scientific publication will be written by the co-investigator 
(Sara Alves Jorge) under the supervision of the sponsor representative and Prof Van den 
Broucke.  A paper will also be written for publication in a peer-journal. Acknowledgements 
will be made to all those who will make this work possible, including healthcare professionals, 
the different institutions and organizations that will be contacted, as well as the older adults 
and informal caregivers who will take part in the study. In addition, some people who will be 
indirectly involved, in particular by giving support and guidance, will also be recognized. 
13. 
ARCHIVING 
 
At the end of the study, the paper data will be stored at the ‘Service des Archives’ from the 
UCLouvain for as long as dictated by local Ethical Committee and Institutional regulations. 
Data to be kept at least 20 years after the trial termination according to the Belgian legislation: 
RD 18 May 2006 art.24 
14. 
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15. 
APPENDIX 
- 
Patient information and consent form 
- 
Questionnaires – older adult and informal caregiver version