Community-based exercise (ComEx Pain) for older adults with chronic musculoskeletal pain: a protocol for a randomised controlled feasibility trial

Trial design

The Community-based Exercise for Chronic musculoskeletal pain (ComEx Pain) study is a randomised, controlled, feasibility trial with a pilot economic analysis and a qualitative process evaluation. This is a parallel-group feasibility RCT with a 1:1 allocation ratio. This trial protocol is presented in accordance with the Standard Protocol Items for Intervention Trials (SPIRIT) guidelines⁴¹ and the checklist of the Consolidated Standards of Reporting Trials extension for feasibility and pilot trials⁴². The ComEx Pain Study is situated within the feasibility and piloting stage of the Medical Research Council (MRC) framework for the design and development of complex interventions⁴³. Completed checklists and other study materials can be found in the Extended data and Reporting guidelines sections⁴⁴.

This trial is registered at Clinical Trials.gov (NCT06535633). The ethics of the study conformed to the 1964 Declaration of Helsinki and its later amendments and was reviewed and approved by the University of Limerick Faculty of Education and Health Sciences Research and Ethics Committee (Reference 2024_02_23_EHS) on 10^th April 2024.

Trial setting

A feasibility RCT will be conducted in the community in the mid-western region of Ireland. There are lightly more than 400,000 people living in the counties of Limerick, Clare, and North Tipperary, which make up the mid-west area of Ireland. Compared to the national comparison, the population in this region is older and more impoverished. In this region, the age group of 75–79 years rose by almost 40% and the age group of 85 years and more by 25% between 2016 and 2022⁴⁵.

The trial intervention is community-based exercise, in the form of group classes led by LSP exercise trainers trained in supporting people with chronic pain. LSP is an inter-agency and multi-sector organisation established as a limited company with the overarching aim of increasing sports participation, ensuring effective use of local resources, coordinating efforts to develop sporting opportunities, and serving as a vital link between local communities and national agencies⁴⁶. LSP is based at the University of Limerick's Sport Arena.

Participants

Sample size

As this is a feasibility RCT, the primary aim is not to evaluate clinical effectiveness; therefore, we will not undertake a formal power analysis for sample size for a primary outcome^47,48. We aimed to recruit 72 participants over a period of two blocks of two-month recruitment periods consistent with the recommendations for pilot studies^49–53, assuming a standard deviation of 2.75 points, at a 5% level of significance and with 80% power, requiring n=62, which we will increase to 72 in order to allow a potential 20% drop out. Data obtained from this pilot RCT will inform the power analysis of a definitive trial⁵⁴.

Eligibility criteria

Participants will be aged 50 or older, report chronic MSK pain of ≥3 months duration, and not currently meet the exercise guidelines of 150 minutes of moderate physical activity per week (determined using the Short form International Physical Activity Questionnaire [IPAQ])⁵⁵.

Exclusion criteria

To ensure participants are safe to exercise they will be screened using subjective measures. Participants will be excluded if they have health conditions that could be worsened by exercise screening using the the physical activity readiness questionnaire (PAR-Q)⁵⁶, (e.g., neurological conditions potentially worsened by exercise or cardiovascular conditions), post-exertional malaise (screened using the DePaul Post-Exertional Malaise Questionnaire⁵⁷), have recently undergone trauma or surgery (less than three months post-surgery), or have significant mobility issues (which would limit exercise participation (participants must be able to mobilise and may use a walking aid). Participants who were unable to communicate sufficiently in English to complete the consent or baseline assessment were excluded.

Recruitment

Limerick City and County have a population of over 205,000, with around 61000 of those over the age of 50. Participants will be recruited via several pathways. Members of the CPI via be informed of the pilot trial through emails, while additional locally focused recruitment is undertaken through advertisements in primary care and community centres, social media posts, the LSP website, and local newspaper advertisements. Potential volunteers will contact the research team and will be sent an electronic link to provide brief study information and screening questionnaires. When screening questionnaires have been returned, the research team will determine eligibility and contact the volunteers to inform them of the outcome. We recruited 36 people over a two-month recruitment period in autumn 2024 and spring 2025 (total sample n=72). The classes will run for a block of eight weeks each in Autumn 2024 and Spring 2025, matching the current calendar of activities for LSP. For each class to run, we will require approximately eight participants to offer the possibility of group engagement but also close supervision from the trainer.

Informed consent

Eligible participants will receive detailed study information and discuss their participation via telephone or in person with one of the research teams. All documents were reviewed and approved by the University of Limerick Faculty of Education and Health Sciences Research and Ethics Committee (Reference 2024_02_23_EHS) on 10^th April 2024. Eligible participants will be invited to ask questions about the study and take time to decide whether they wish to participate. If they agree to participate, they will be asked to provide written consent, either in person or via post.

Randomisation and allocation concealment

Randomisation will be carried out by the trial statistician (ZE) using R (R Core Team and the R Foundation for Statistical Computing)⁵⁸ to perform randomisation with an allocation ratio of 1:1. Allocation will be concealed from participants and researchers until after consent has been obtained, and baseline evaluations will be performed.

Blinding

Due to the nature of the intervention, trial participants and exercise trainers cannot be blinded to the group allocation. The outcome assessor will be blinded to the group allocation, and the trial statistician will be blinded to the allocation for secondary analysis.

Interventions

Intervention arm

In response to feedback from the PPI panel of older adults and CPI, we identified that exercise trainers needed to be trained in a biopsychosocial approach to pain education, helping them to adopt positive pain beliefs and equipping them with the skills to support people with chronic MSK pain to successfully engage in exercise. Trainers have undertaken a one-day interactive education programme, led by academics with extensive experience in pain education and physical activity (KOS & CR) and involving PPI representatives who had lived experience of chronic MSK pain. The content of this programme was based on pain science education material^59,60 developed for public health campaigns (www.flippinpain.co.uk and www.pain-ed.com), incorporating feedback from both the CPI and PPI panel of older adults. Exercise trainers were trained to adapt exercise content to a wide range of physical abilities, provide basic advice on pacing and flare-ups of pain, and use positive language to maintain physical activity in the presence of pain.

The exercise trainers who are educated in chronic pain, will lead a set of classes that are adapted to the needs of people with chronic pain. We consulted with members of the CPI to understand the barriers and facilitators for community-based exercise and their needs in relation to same. A forthcoming publication reported the results of a survey of (n=130) members of CPI highlighting that key barriers to community-based exercise included fear of pain exacerbation and lack of skilled exercise instruction. Access to an exercise trainer educated in supporting people with chronic pain was the most commonly cited facilitator of engagement in exercise chosen by the respondents. Focus groups with people with chronic pain detailed the important factors to consider when planning an exercise intervention; that is, the activity should be enjoyable, non-competitive, and accessible to all levels of physical activity, and the venues should also be physically accessible with good transport links, and in an environment conducive to exercising out of extreme weather or cold. The exercise modalities of choice were informed by the survey results, as well as alignment with the LSP class offerings and trainer competency. We will offer classes focused on aquatic exercise, activator pole walking, yoga or Pilates, and circuit-style fitness for participants to choose their own preferred option. Classes will run weekly for 60 min for 8 weeks in various community venues in Limerick City and County, including a public swimming pool, community centre, and outdoor park. The intervention group will receive a paper-based education manual about physical activity and pain management designed for people with chronic pain, based on pain science education.

Control arm

The control group will receive the same paper-based education manual as the participants in the intervention arm regarding physical activity and pain management education designed for people with chronic pain and based on pain science. This manual will be supplied to participants in the control group by post, who will also continue with the usual care for their chronic pain. Based on PPI feedback suggesting the importance of equity for all volunteers to take part, those in the control group will be offered the opportunity to participate in the intervention (group exercise classes) after completing their final follow-up assessments.

Relevant concomitant care permitted or prohibited during the trial

If a participant experiences any serious adverse events during the study that might be connected to the program or interfere with their ability to engage in it safely, they will be required to stop the program (e.g., chest discomfort or an injurious fall). In the instance of a participant having a significant adverse event they would require further medical assessment and GP assessment to continue their participation. Additionally, participants may decide to stop participating in the program at any moment for any reason.

Patient and Public Involvement (PPI)

The programme was developed in conjunction with a local PPI panel of older adults in the mid-west of Ireland⁶¹ and members of CPI. To ensure the relevance of research outcomes, it is essential that the views and experiences of people living with chronic pain are considered when designing research⁶². This PPI panel and members of CPI have been instrumental in our research processes thus far. PPI activities have contributed to the research design, outcome measure selection, intervention planning, exercise trainer training, program title, recruiting techniques, and informational posters and leaflets. Future contributions of the PPI panel will include are expected to cover all facets of research planning and execution, participation in progress meetings, result interpretation, dissemination and communication of research findings, and development of a sustainable community-based intervention. The PPI panel is compensated for their participation, and there are also flexible options for participating through in-person or online sessions.

Criteria for discontinuing or modifying allocated interventions

A traffic light system with quantitative thresholds will be used as a guide to judge the feasibility and progression, as shown in Table 1. The quantitative thresholds for each feasibility criterion were determined based on an educated guess before recruitment. The feasibility of proceeding to a definitive trial of ComExPain will be determined by the achievement of the following criteria: ≥ 50% of volunteers will be eligible to participate in the first recruitment phase, ≥ 50% of eligible participants will consent to participate, ≥ 60% will adhere to group exercise sessions, and more than 80% of outcome measures will be completed. These criteria will be applied by the Trial Steering Committee, examining the data from the first recruitment and intervention phase in Autumn 2024 to determine any alterations that need to be made for the second recruitment phase in Spring 2025.

Data collection and outcomes

The following data will be collected during the trial.

Primary outcomes

Feasibility outcomes: Data from screening, recruitment, and follow-up logs will be used to generate realistic estimates of eligibility, consent, recruitment, and follow-up rates.

Outcome measurement completion rates will be reported, with a target of at least 80% of the included participants with valid baseline and follow-up outcome data (attrition rate <20%).

These data, along with the qualitative interviews, will be used to measure adherence and assess whether any modifications are required to improve engagement.

Secondary outcomes

The secondary outcomes piloted for a future definitive study were chosen based on the recommendations for core outcomes in chronic pain clinical trials⁶³ where it is advised that six domains should be represented: 1) pain, (2) physical functioning, (3) emotional functioning, (4) participant ratings of improvement and satisfaction with treatment, (5) symptoms and adverse events, and (6) participant disposition (e.g., adherence to the treatment regimen and reasons for premature withdrawal). The subheadings below indicate the measures chosen for each of these domains.

All outcomes below will be measured at baseline and at the end of the 8 week intervention (or equivalent control period).

Pain: Numerical Rating Scale for average pain intensity

Pain intensity will be measured as average pain for the previous week using a 0-10 Numerical Rating Scale (NRS). The NRS has been shown to have acceptable reliability and validity in a range of chronic pain populations^64,65.

Function: Pain Disability Index

The Pain Disability Index (PDI) is a 7-item questionnaire used to investigate the magnitude of self-reported pain-related disability, independent of the region of pain or pain-related diagnosis. The items of the questionnaire are assessed on a 0–10 numeric rating scale, in which 0 indicates no disability and 10 indicates maximum disability. The sum of the seven items equals the total score of the PDI, which ranges from 0 to 70, with higher scores reflecting greater interference of pain with daily activities. It has been widely validated in patients with chronic musculoskeletal pain⁶⁶.

Emotional function: Hospital Anxiety and Depression Scale

The HADS was originally a 14-item questionnaire used to assess the levels of depression and anxiety in hospital patients. It has been widely used in chronic pain research, but a recent factor analysis involving over 2500 people with chronic MSK pain showed that an 11-item version was a more valid and reliable measure of emotional distress related to pain than the full instrument; therefore, we will use the 11-item version in a feasibility study⁶⁷.

Rating of satisfaction/improvement: Global rating of Change

Rating overall improvement has been recommended as a core outcome in chronic pain; therefore, we will include a Global Rating of Change score designed to quantify a participant’s improvement or deterioration over time⁶⁸. We will use a 7 numbered scale balanced in the centre with “unchanged,” and anchored with “very much worse” on the left, and “completely recovered” on the right” and the following prompt: With respect to your pain problem, how would you describe yourself now compared to when you began the study?

Adverse Events: Subjective report

Participants in both groups will be instructed to report any adverse events using an electronic patient log. Exercise trainers will also be asked to record any adverse events reported to them or observed during exercise classes.

Physical activity: The use of both objective (accelerometery) and subjective (International Physical Activity Questionnaire) measures of physical activity in this feasibility study will allow us to evaluate whether the additional burden of objective measurement is worthwhile in terms of providing important information that is not captured by subjective reports alone.

Objective: The time spent sitting, standing, lying down, and time spent in moderate and vigorous intensity aerobic physical activity (MVPA) will be measured using ActivPAL™ (PAL Technologies Ltd, Glasgow, UK). ActivPAL™ is a small, lightweight activity monitor that classifies an individual's free-living activity into time periods spent in sedentary, standing, and walking positions using proprietary algorithms^69–71. ActivPAL™ is a uniaxial accelerometer that produces signals related to thigh inclination. ActivPAL™ also records step count, that is, the number of steps taken, and transition count, that is, the number of movements from lying/sitting positions to standing and vice versa. ActivPAL™ will be worn for seven days at baseline and seven days after the completion of the exercise intervention. Participants will attend the University of Limerick to be fitted with the device and receive instructions on its use.

Subjective: We will use the International Physical Activity Questionnaire (IPAQ), which measures the duration and frequency of physical activity over the preceding 7 days across a range of domains, including leisure time, domestic and gardening activities, and work-related and transport-related activities, and has been shown to be reliable in populations with chronic MSK conditions⁷².

Health Related Quality of Life: EQ-5D-5L

We will use the EQ-5D-5L, a valid response measure of health-related quality of life, covering five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression⁷³. It has been shown to be valid and reliable in people with chronic MSK pain⁷⁴.

Economic evaluation

Given the stage of development of ComEx Pain, an economic evaluation will primarily seek to examine and help establish the resources required for this complex intervention. Our healthcare utilisation survey will use relevant questions from the Irish Health Survey. The Irish Health Survey (IHS) is the Irish version of the European Health Interview Survey (EHIS) and has been collected in its current format since 2015. The economic evaluation will also seek insights from qualitative research to better understand the opportunity costs related to this alternative model of facilitating physical activity. We will ask questions relating to usage of hospital inpatient and outpatient care, GP consultations (in person, home visits or phone/virtual) as well as consultations with nurse practitioners, dentists/orthodontists, physiotherapists/osteopaths/chiropractors, mental healthcare professionals, and any interactions with consultants in these professions. We will ask whether the healthcare services were provided by the state or were covered by insurance companies as well as any out-of-pocket expenses incurred by the participant. Most economic evaluations of interventions to improve health take a "human capital approach" in that they quantify the effect of the intervention on labour market participation, hours worked, and earnings. However, given the participants age and diagnoses they are less likely to be employed, therefore we will instead focus on measuring the intervention's effect on their well-being.

To measure well-being, pre- and post- intervention, we will administer the EQ-5D-5L questionnaire. This is a standard measure of well-being that used in economic evaluations of healthcare interventions for over 30 years. The evaluation will be conducted in a manner consistent with the guidelines published by the Health and Information Quality Authority in Ireland to derive a single index of wellbeing/utility that is reflective of the Irish population's valuation of health states⁷⁵. The objective of the evaluation will be to identify, quantify, and compare the cost and effect of the Com Ex Pain intervention relative to those under the status quo provision of care (i.e., control group). The incremental costs and effects of the programme relative to usual care will be calculated through incremental cost-effectiveness analysis and will aim to calculate the incremental cost-effectiveness ratio (ICER). The ICER is formally denoted as follows:

Qualitative evaluation

During the feasibility and piloting phase, process evaluations can play a crucial role in understanding the feasibility of an intervention and optimising the intervention design and evaluation⁷⁶. In line with the guidelines on the conduct of process evaluations⁷⁶, the embedded qualitative process evaluation aims to (1) explore stakeholders’ views on the intervention acceptability and mechanisms through which the intervention has an impact, (2) assess what is delivered to participants in both trial arms, and (3) describe the contextual factors impacting the intervention and its outcomes.

This will be achieved by:

Interviews will be conducted via Microsoft Teams by a researcher who is not involved in recruitment, consent, or any other trial processes. All interviews will be audio-recorded and transcribed within the MS Teams.

Qualitative analysis

Interview data will be transcribed in full and analysed alongside field notes recorded during observation using an inductive reflexive approach to thematic analysis^77,78. This approach acknowledges and considers the centrality of a researcher’s subjectivity. Reflexivity enables the researcher team to consider and analyse how subjective and intersubjective elements influence the research process. The analysis will be facilitated using NVIVO 12 qualitative data analysis⁷⁹. When coding is complete, all participants will be invited to “member check.” The PPI panel will review and discuss the preliminary analysis of the interview data and contribute to the process of identifying themes. The PPI panel of older adults and CPI will be invited to co-write and design a lay summary and infographics of the findings. Group video/phone conferences or one-to-one telephone calls will be scheduled to enable the participants to contribute to the analysis.

Data analysis

All data will be analysed and reported in accordance with the CONSORT guidelines for pilot and feasibility trials⁴² and the CONSORT extension for reporting patient-reported outcomes⁸⁰. As this is a feasibility study with a relatively small sample size, formal hypothesis testing is not appropriate⁸¹; rather, the purpose of any analysis will be to generate estimates to inform the planning of the definitive future trial. The analysis will be conducted in two stages. Stage 1 will summarise the feasibility outcomes. Stage 2 will summarise the secondary outcome data at eight weeks. As it is inappropriate to use feasibility trial data to formally test for between-group treatment effects, the analyses will be primarily descriptive in nature⁴⁷. Descriptive statistics of the clinical outcome data will be calculated for each group. Interval estimates of the potential intervention effects, relative to the control intervention, will be produced in the form of a 95% confidence interval to ensure that the effect size subsequently chosen for powering the definitive trial is plausible. This will refine the design of future definitive trials.

Determining progression to the full trial

The primary feasibility outcomes will provide key information on the viability of future definitive trials. Our recruitment and refusal rates will provide information on whether we can recruit an adequate number of older adults with chronic musculoskeletal pain for randomisation in a future definitive trial. Retention and adherence rates will allow us to determine the potential dropout rates in a definitive trial. Secondary outcomes will permit calculation of the correct sample size for future trials and indicate potential effects of the intervention. We shall progress to a full trial application if the minimum success criteria are achieved in key feasibility aims and objectives as per the Traffic Light System.

Trial oversight and monitoring

The ComEx Pain trial will be conducted in accordance with the international standards of good practice in clinical trials (ICH GCP Good Clinical Practice). A Trial Management Group (TMG) and Trial Steering Group (TSG) have convened to ensure adequate trial management, governance, and safety monitoring for the trial. The TSC will provide overall supervision of the study, in particular, monitor study progress, and provide public, clinical, and professional advice, with pre-agreed terms of reference. The Trial Management Group will be responsible for the day-to-day management of all study procedures, meeting on at least a monthly basis. The Health Research Institute (HRI) Clinical Research Support Unit Limerick (CRSU Limerick) will provide support for document development, data quality, data storage, and archiving of data in line with good clinical practice (GCP) standards as well as FAIR (findable, accessible, interoperable, and reusable) principles for scientific data management and stewardship.

Data management, audit and monitoring

All relevant data entered will be stored in Excel and pseudo-anonymised. The lead author will maintain the key to this pseudo-anonymization. An independent researcher will complete a quality check of 20% of the data. If more than 5% of errors are identified across the data entry, all data will be independently checked by the second independent researcher. For the lifetime of the study, the pseudo-anonymised data will be stored in an encrypted and password-protected electronic data capture system.

The confidentiality of the data will be always ensured by the PI and all members of the research team. Identifiable data will not be disclosed to third parties and no participant’s name will appear in any of the results, as indicated in the participant’s information leaflet. Each participant in the study will be assigned a numerical code to link the data collected at baseline to the data collected at follow-up. Aggregate data will be pseudo-anonymised. The research team will ensure that anti-virus software is installed on all devices involved in data entry. All information trafficked from the site to the research database will be pseudo-anonymised with unique study-specific subject numbers. Access to the research database is managed by the PI. Only coded/pseudo-anonymised data will be transferred to external sites.