Research questions

The pilot aims to address uncertainties regarding the feasibility of study methods. This includes researching strategies to tackle recruitment and retention challenges, ensuring a representative and diverse sample of patients with T2DM for the trial-based economic evaluation [14]. Moreover, acknowledging the high workload and time constraints experienced by HCPs, we aim to gain insights into how to minimize burdens on participating primary care practices [15,16]. Finally, considering the complexity of the measurement process and the understandability of the measurement tools, the outcomes and costs will be measured in the pilot study to refine study procedures for the trial-based economic evaluation. Therefore, the research questions of this pilot study are:

1. What strategies can be employed to effectively recruit and retain a demographically and clinically diverse sample of patients with T2DM?
2. How can we support primary care practices in effectively managing the challenges associated with study participation?
3. How can we feasibly measure relevant SDM outcomes, treatment adherence, health outcomes, and costs from a societal perspective for T2DM using valid and reliable measurement instruments?

Setting

The majority of patients with T2DM in the Netherlands (90% in 2022) are treated in a primary care setting organized by care groups [23]. Care groups are collaborations between HCPs (general practitioners and affiliated personnel) and are responsible for organizing, coordinating, and providing care for patients with T2DM in their region [24]. A team comprising of a general practitioner and a practice/diabetes nurse provides treatment following the national guidelines for T2DM of the Dutch College of General Practitioners (NHG) [25]. Since most Dutch patients with T2DM are treated in primary care, the multistage SDM program was developed based on the NHG guidelines for T2DM and will be pilot-tested in a general practice setting. We collaborate with the primary care group ‘Huisarts & Zorg’, a group of 75 general practices located in the region of Gorinchem (a municipality in South Holland) to recruit practices and patients. Four primary care practices from the care group ‘Huisarts & Zorg’ will be included in this pilot study.

Study design

The multistage SDM program will be piloted in a cluster-randomized controlled trial using a convergent parallel mixed-methods approach to answer questions related to sample recruitment and retention, study management, and feasibility of outcome and cost measurements. Randomization will be conducted by cluster (i.e., primary care practices) to avoid possible contamination between the intervention and control group [26]. Two primary care practices will be randomly assigned to the intervention group and two to the control group. Simple randomization will be used to assign each primary care practice to a group with an equal probability (1:1 allocation) using a computerized random number generator [27]. Patients with T2DM and HCPs are not blinded to their assigned group. Patients and HCPs from the intervention practices will have access to the multistage SDM program. They will receive an account to gain access to the PatientPlus platform, where the PDA is available. Patients and HCPs from the control practices will provide and receive usual care according to the NHG guidelines for T2DM [25]. They will not have access to the multistage program. Data will be collected from patients and HCPs in both the intervention and control practices.

Participants

To be able to recruit a diverse population of patients with T2DM, we aim to include general practices from the care group ‘Huisarts & Zorg’ that differ in terms of the sociodemographic background of their patient panels. HCPs from the participating practices will be asked to recruit patients who: 1) are eighteen years or older; 2) need to decide on T2DM treatment based on the NHG guideline (medication and/or lifestyle); and 3) speak Dutch at a necessary level to complete questionnaires and ensure involvement in SDM. We will only exclude patients with severe cognitive impairments that hamper SDM. Patients will be enrolled in the study after receiving face-to-face and written information about the study from their HCP and after giving written informed consent.

Intervention

The multistage SDM program combines an online PDA with a preparatory consultation for patients as well as an interprofessional training in the PDA and SDM for HCPs (Fig 2). The program was co-created with a multidisciplinary steering group representing all relevant stakeholders in Dutch diabetes care. The development of the PDA for T2DM is described in detail elsewhere [5].

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Fig 2. Overview of the multistage shared decision-making program for type 2 diabetes mellitus.

SDM: shared decision-making; PDA: patient decision aid; T2DM: Type 2 Diabetes Mellitus.

https://doi.org/10.1371/journal.pone.0300944.g002

The PDA is available in the online catalog of PatientPlus (https://www.keuzehulp.info/front-page/keuzehulpen/diabetes-type-2, Dutch only), the largest supplier of PDAs in the Netherlands. In line with the International Patient Decision Aids Standards (IPDAS) guidance, the PDA comprises of five sections: 1) information about T2DM and the available treatment options; 2) a comparison of treatment options based on, for example, the risk of cardiovascular disease and effect on daily life; 3) questions to assess patients’ knowledge; 4) value-clarification exercise; and 5) summary of the patient’s journey [28,29].

To prepare and empower patients for SDM, our multistage program comprises a one-to-one preparatory consultation with a trained facilitator. Each practice can decide whether a practice nurse, medical assistant or other HCP will serve as a trained facilitator. The consultation will last 20–30 minutes and is intended to help patients effectively use the PDA and provide them with the knowledge and confidence needed to fully participate in SDM. The preparatory consultation takes place before the clinical encounter where the treatment decision is made by a patient and HCP (i.e., a general practitioner or specialized nurse who can prescribe medication).

All participating HCPs (including the trained facilitators) from included intervention practices receive a 2-hour interactive interprofessional training in SDM and the PDA, including communication techniques and general instructions to increase SDM knowledge. HCPs will receive accreditation for their participation in the training. The training is offered by PatientPlus. One intervision meeting between the trained facilitators from all participating practices will be held to stimulate interprofessional training.

Sample size calculation

The pilot study is a preparation for a large trial-based economic evaluation and therefore setting the sample size for the pilot study in order to minimize the total sample size of the pilot study and main trial together is the most suitable method of sample size calculation [30]. The sample size calculation for the pilot study is based on a 90% powered main trial and an estimated medium (between 0.3 and 0.7) effect size in the decisional conflict score (primary outcome of the trial-based economic evaluation) [31]. The decisional conflict score was chosen as the primary outcome as it captures the patient’s uncertainty and quality of the decision-making process, which aligns with the outcomes of the multistage SDM program [32]. Moreover, it is a validated questionnaire that is widely used in PDA-supported SDM research. Using the stepped rules of thumb, the sample size for the pilot study would be 30 patients with T2DM [30]. Due to possible loss to follow-up and drop-out, the sample size will be increased by a third. Thus, the sample size for this pilot study will be set at 40 patients with T2DM, with 20 patients assigned to each arm.

Outcome measures

The pilot study focuses on three aspects: 1) sample recruitment and retention; 2) study management; and 3) feasibility of outcome and cost measurements. Each aspect has its own relevant outcome measures and measurement instruments.

Research question 3. Feasibility of outcome and cost measurements.

We will assess the feasibility of primary and secondary outcome measurements of the future trial-based economic evaluation. The primary and secondary outcomes will solely be measured to assess its measurement feasibility and not to determine the (cost-) effectiveness and cost-utility of the multistage SDM program. The primary outcomes focuses on short-term SDM outcomes. Primary outcomes include patient decisional conflict (using the 16-item Decisional Conflict Scale, DCS [32]), level of SDM as perceived by patients (based on the 3-item CollaboRATE survey [33,34] and SDM-Q-9 questionnaire [35]), level of SDM as perceived by HCPs (using the SDM-Q-Doc questionnaire [35]), and patient knowledge (with 9 tailor-made questions assessing patient’s understanding of the glucose-lowering treatments). The DCS, CollaboRATE, SDM-Q-9, and SDM-Q-Doc questionnaires will be used due to their validity and wide applicability in assessing SDM in healthcare. The long-term cost-effectiveness and cost-utility of our multistage SDM program will serve as secondary outcomes in the trial-based economic evaluation. To compare the multistage program with usual care and estimate the costs of improving individual’s quality of life, it is essential to assess societal costs and health-related quality of life for conducting a cost-utility analysis [36]. In the future trial-based economic evaluation, we will also conduct a cost-effectiveness analysis to estimate the costs of achieving improvements in relevant health outcomes (i.e., glycemic control). Therefore, secondary outcomes include glycemic control (HbA1c obtained via the HCP), societal costs (measured with an adapted version of the iMTA Productivity Costs Questionnaire (iPCQ) and iMTA Medical Consumption Questionnaire (iMCQ) [37,38]), health-related quality of life (measured with the Dutch EuroQol (EQ) 5D-5L questionnaire assessing quality of life [39]), and medication adherence (measured with the Medication Adherence Report Scale [40] and prescription data obtained via the pharmacist).

Table 1 provides an overview of the primary and secondary outcomes of the future trial-based economic evaluation, including their measurement tools. We will conduct semi-structured interviews with patients to gain insights into the understandability and accessibility of the measurement tools. Interviews will be conducted either in person or online via Microsoft Teams, depending on the patients’ preference. Participation in the interviews is optional for patients. They can indicate their consent to be contacted for an interview by selecting the appropriate option in the informed consent form. A topic list will be developed to guide the interviews. Moreover, we will collect data on the usage behavior of patients when completing the questionnaires (i.e., time needed to complete questionnaires) and the amount of missing data. The focus groups with HCPs from participating practices will also be used to evaluate the understandability of the SDM-Q-Doc questionnaire.

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Table 1. Outcomes of the future large-scale trial-based economic evaluation, including their measurement tools.

https://doi.org/10.1371/journal.pone.0300944.t001

Data collection and timeline

The pilot study is planned to run for 18 months, from early November 2023 to late April 2025. Patient recruitment and data collection are scheduled to take place from February 2024 to January 2025. This will be followed by data analysis and reporting. Patients from the intervention practices are requested to complete questionnaires via the online PatientPlus platform and patients from the control practices will complete questionnaires via Qualtrics [41]. They will receive automatic email reminders to complete the follow-up questionnaires at the 3- and 9-month follow-up. Additionally, automated reminders will be sent if the patient has not yet completed the questionnaire. HCPs from the control and intervention practices will complete the questionnaire via Qualtrics [41]. The schedule of study enrolment and assessment can be found in Fig 1. Baseline measurements will capture sociodemographic and clinical patient characteristics, patient knowledge, medication adherence, costs, and health-related quality of life. In both study arms, patients complete the DCS, CollaboRATE survey, and SDM-Q-9 questionnaire directly following the clinical encounter where a treatment decision is made. At the same time, HCPs complete the SDM-Q-Doc questionnaire. Follow-ups at 3 and 9 months will facilitate the measurement of medication adherence, costs, and health-related quality of life. Semi-structured interviews with patients will be held within one month of study participation and the focus groups with HCPs from participating practices will be held at the end of the 9-month implementation period. After completing data collection at the 9-month follow-up, we will gather information on the glycemic control of participating patients by obtaining their HbA1c values at baseline, and 3- and 9-month follow-ups, through their primary care practice.

Data analysis

Descriptive statistics will be presented as counts and percentages for categorical variables. For continuous variables, mean and standard deviation will be reported for normally distributed data. If the data is not normally distributed, the median and interquartile range (IQR) will be reported instead. The variables include sociodemographic and clinical characteristics, outcomes of the future trial-based economic evaluation, and estimates related to feasibility (e.g., recruitment rates and time to complete questionnaires). Moreover, we will analyze the missing data by identifying the amount of missing data and complementing this information with the results of the qualitative analysis. This involves cross-referencing the amount of missing data with patient interview results, where insights into the understandability of the questionnaires are gathered. Additionally, during focus groups with healthcare professionals, possible factors influencing incomplete questionnaires or patient dropout will be discussed. Descriptive analysis will be performed in Rstudio [42]. Due to the nature of the pilot study, no statistical tests on the primary and secondary outcomes will be conducted.

Interviews and focus groups will be audio-recorded, transcribed ad verbatim, and anonymized to protect participant’s confidentiality. The data will subsequently be analyzed in ATLAS.ti using thematic analysis with an inductive approach following three steps [43,44]. First, the transcripts will be read and re-read in a process called ‘familiarization’ to gain an in-depth understanding of the data. Second, phrases, sentences, and paragraphs with meaningful topics will be extracted and labeled with a code for each interview transcript, with this process conducted independently by two researchers. An initial codebook will be developed based on the interview guide, and codes will be added and adjusted as they emerge from the data. The coded transcripts from both researchers will be compared, and discrepancies will be discussed to promote reflexivity. Inter-coder reliability will be established and maintained throughout the coding process. Third, themes are developed by clustering codes with similar meanings or interrelations, to understand, interpret, and report the main insights flowing from the data. The analysis of the interviews and focus groups will be used to improve the questionnaires (e.g., question formulation and possible adaptations to the cost questionnaire), recruitment strategies, and study procedures.

The data management process (i.e., data collection, data processing, data quality, and data analysis) and possible improvements thereof will be discussed with the research team in three 2-hour meetings throughout the study period.

Data monitoring and quality control

The data will be internally monitored by a member of the research team, ensuring accuracy in data entry and completeness to maintain data integrity. The research team will also track patient enrollment and recruitment rates across the participating general practices, as well as monitor consent forms to ensure ethical compliance. To ensure correct integration of the PDA into clinical practice, participating HCPs from the intervention practices will receive training in SDM and using the PDA. Throughout the study, the research team will maintain regular contact (via phone or email every three months) with the general practices to gather continuous feedback on recruitment and implementation of the program. Additionally, an intervision meeting with HCPs from the intervention practices will be held to address potential challenges and to collect data on how each practice is implementing the multistage SDM program.

Ethical considerations and declarations

The Medical Ethics Review Committee of the academic hospital of Maastricht (azM) and Maastricht University confirmed that the Medical Research Involving Human Subjects Act does not apply to the pilot study and that official approval is not required (METC2023−0114). See Supplementary File 3 for the full protocol approved by the Medical Ethics Review Committee. Patients will be enrolled in the study after receiving face-to-face and written information about the research and after giving written informed consent. Participants’ data will be used and retained by the researchers of Maastricht University in compliance with the EU General Data Protection Regulation. Some of the data will be collected via PatientPlus. PatientPlus has an information security management system that is ISO27001 and NEN7510 certified. Researchers will be provided with an account for PatientPlus to access the research data of patients. PatientPlus has only access to the anonymized data. The collected data will be stored on the protected server of Maastricht University. All participants in this study will be given an ID number to ensure their confidentiality. Data in reports and publications of this pilot study will not be traceable to the research participants. Research participants have the right to withdraw from the research and withdraw their consent to the use of personal data at any time during the study. The data from the pilot study will be available upon request.

Dissemination plan

The results of this pilot study will be disseminated via conference presentations and international peer-reviewed scientific journals. Moreover, attention will be given to promoting the multistage SDM program among patients with T2DM and HCPs within primary care. This will help the future recruitment of patients with T2DM and primary care practices for the trial-based economic evaluation. Our collaboration with the steering group, consisting of patients with T2DM, patient organizations, and HCPs, established at the beginning of the development of the multistage SDM program, will be continued. The steering group and our collaboration with care group ‘Huisarts & Zorg’ and PatientPlus add valuable expertise and experience from practice and policy as future end-users of our multistage SDM program. This collaboration will improve the implementation and dissemination of the program.