Overweight or ObesityBO2WLNCT05811624
Lifestyle Intervention in Overweight/Obese Chronic Low Back Pain (CLBP) Patients: an International Multi-center RCT
A study testing Physiotherapy intervention, including behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy. and Physiotherapy intervention, including pain neuroscience education and cognition-targeted exercise therapy alone. in people with Overweight or Obesity and Chronic Low-back Pain, run by Vrije Universiteit Brussel at 2 sites in 2 countries.
Trial summary
Chronic low back pain (CLBP) is the most expensive cause of workrelated disability: it causes the highest number of years lived with disability. The most severe and debilitated CLBP patients often have comorbidities such as overweight and obesity. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Overweight or Obesity, Chronic Low-back Pain
- What is being tested?
- Physiotherapy intervention, including behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy. and Physiotherapy intervention, including pain neuroscience education and cognition-targeted exercise therapy alone.
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 252 participants
- Where
- 2 sitesin 2 countries
- Study dates
- 13 Apr 2023to Nov 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults (18 - 65 years)
- Overweight (BMI ≥ 25 kg/m2) or obese (BMI ≥ 30 kg/m2) women and men.
- CLBP (n=252), which is defined as nonspecific low back pain for at least 3 months duration, currently seeking care for low back pain and leg pain not ≥ 7 (on a maximum of 10) on a numeric rating scale.
- Continue usual care 6 weeks prior to (to obtain a steady stat) and during study participation.
- Depending on the country of inclusion: Native Dutch speaker (for Belgium) or Native German speaker (for Switzerland).
Who cannot join
- Patients with BMI ≥ 40 kg/m² will be excluded as people being morbid obese are eligible to undergo abdominal surgery. Because BMI may not always correspond to the same body fat percentage in different individuals (e.g., athletic types with higher muscle mass may also have BMIs ≥ 25 km/kg²), each participant's body fat percentage will be measured using the TANITA and compared to the body fat percentage reference values. Participants with exceeding BMI but falling into the healthy fat percentage range (which is sex-, age- and ethnicity dependent will be excluded.
- Pregnant, currently breastfeeding or given birth in preceding year.
- Currently receiving dietary or exercise interventions or received in the past 6 weeks.
- Show evidence of specific spinal pathology based on self-report (e.g., hernia, spi-nal stenosis, spondylolisthesis, infection, spinal fracture or malignancy), or a se-vere underlying comorbidity specific diagnoses that interfere with treatment (e.g., diagnosed diabetes, cardiovascular problems, metabolic diseases)
- Other severe diseases based on current medication intake or being currently treated by a medical doctor for a specific diagnosis, (e.g. diagnosed eating disorders).
- Ongoing problems or cases with insurance companies regarding their back.
Trial locations and contacts
2 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
Jo Nijs, PhD contact
2 sites in 2 countries
Belgium1 site, 1 recruiting
- Recruiting
Vrije Universiteit Brussel
Brussels, 1090
Anneleen Malfliet, PhD, anneleen.malfliet@vub.be
Matteo Van Roose, MSc, Matteo.vanroose@vub.be
Switzerland1 site, 1 recruiting
- Recruiting
Berner Fachhochschule
Bern, 3012
Heiner Baur, heiner.baur@bfh.ch
Melanie Liechti, MSc, melanie.liechti@bfh.ch
About this study
Official title: Lifestyle Intervention in Overweight/Obese People Suffering From Chronic Low Back Pain: an International Multi-center Randomized Controlled Trial
Chronic low back pain (CLBP) is the most expensive cause of workrelated disability: it causes the highest number of years lived with disability. The most severe and debilitated CLBP patients often have comorbidities such as overweight and obesity. Despite the growing body of scientific literature pointing towards the close interaction between overweight/obesity and CLBP, few treatment programs for people with CLBP nowadays take overweight into account. Therefore this study will examine the added value of a behavioral weight reduction program (changes in diet, behavior and physical exercise) to current best evidence rehabilitation (pain neuroscience education plus cognition-targeted exercise therapy) for overweight or obese people with CLBP. An international, multicenter randomized controlled trial comparing a behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy versus pain neuroscience education and cognition-targeted exercise therapy alone, will be conducted. The primary outcome is pain and the primary endpoint was chosen at 12 months follow-up; secondary outcomes include health care use and daily functioning (see detailed description of outcomes for an overview of all secondary outcomes). If the promising results of the proof of concept study are corroborated, the new intervention will have a high socio-economic impact, including an annual health care cost reduction of €66 million in Switzerland, and €60 million in Flanders, and is expected to increase life expectancy in the long term.
Read the detailed description
Rationale:
Chronic low back pain (CLBP) is the most common and important clinical, social, economic, and public health problem of all chronic pain disorders across the world. In addition to its high prevalence, CLBP is a severely disabling disorder characterized by tremendous personal and socioeconomic impact. Furthermore, it is the most common cause of work-related disability, generating long-term sick-leaves, and it causes the highest number of years lived with disability.
The most severe and debilitated CLBP patients often have comorbidities such as overweight and obesity. In fact, pain intensity and disability in people with CLBP show dose-responses to body mass index (BMI), waist circumference, percent fat and fat mass. Ample studies and several meta-analyses indeed confirm that overweight and obesity are associated with LBP, with overweight and obesity even being a risk factors for low back pain. Regarding socio-economic impact, overweight or obesity is not only related to LBP persistence, but also to higher rates of health care seeking for LBP. Obviously, people with CLBP who are overweight or obese, are likely to have more complex health needs requiring focus on lifestyle behavioral factors such as physical activity/exercise and diet.
CLBP is a complex disorder which is difficult to treat. Exercise therapy is an evidence-based treatment for CLBP both general exercises and cognition-targeted exercise therapy have shown beneficial effects on pain in patients with CLBP. Unfortunately, current treatments for CLBP apply a 'one-size-fits-all' approach and do not address comorbidities like obesity. This knowledge gap is now acknowledged internationally: overweight and obesity are increasingly recognized as a plausible therapeutic target for people with CLBP. Despite the growing body of scientific literature pointing towards the close interaction between overweight/obesity and CLBP few treatment programs for people with CLBP nowadays take overweight into account.
Few studies explored the added value of weight reduction to the management of people with CLBP. Yet, proof of concept for combining dietary changes with exercise therapy for patients with CLBP and comorbid overweight/obesity show promising results. Here we propose studying the added value of a behavioral weight reduction program (changes in diet, behavior, and physical exercise) to blended rehabilitation (PNE plus CTET) for overweight or obese people with CLBP. Both treatments are effective in their specific target population (i.e., behavioral weight reduction for overweight/obese people and PNE plus CTET for people with CLBP and normal BMI), but whether their combined approach is cumulative in overweight/obese people with CLBP is currently unknown and represents an important research priority.
Objectives:
The primary objective is to examine if a behavioral weight reduction program combined with Pain Neuroscience Education (PNE) and Cognition-Targeted Exercise Therapy (CTET) is superior to reduce pain at 12 months follow-up compared PNE and CTET alone, in overweight or obese people with CLBP.
Secondary objectives are to examine the effects of adding a behavioral weight reduction program combined with PNE and CTET, compared to PNE and CTET alone, on 1) other pain related outcomes (pain interference, pain distribution and pain beliefs), 2) on anthropometrics (body weight/composition, muscle thickness and fat distribution), 3) on energy balance related behavior (24h continuous activity monitoring, dietary intake and sleep) and finally 4) on health economics (heath care utilization, productivity loss and quality of life) at 12 months follow-up.
Interventions:
Both interventions (experimental and control) are organized equally: all participants will receive 18 treatment sessions over a 14-week period see table 2 for a detailed overview. Rather than practical, treatment arms will differ in content.
The control intervention will consist of a total of 18 treatment sessions distributed over 14 weeks. It comprises of only the chronic-pain-focused interventions: 3 sessions of PNE in the first 2 weeks \& secondly, 15 sessions of CTET in the remaining 12 weeks.
The experimental intervention will consist of a total of 18 treatment sessions distributed over 14 weeks. The first part will consist of chronic-pain-focused interventions: firstly, 3 sessions of PNE in the first 2 weeks \& secondly, 15 sessions of CTET in the remaining 12 weeks. The second part will consist of a more weight-reduction-focused intervention. The weight reduction intervention is a lifestyle approach that will be integrated in the CTET intervention, implying that grading daily physical activity and exercise levels will aim at reducing weight (i.e. together with a change in diet we aim at a caloric deficit of 500 to 700 kcal/day) and improving pain cognitions at the same time.
Study design:
Randomized controlled trial with follow-up assessments directly post-treatment (T1), 3 months post-treatment (T2), 6 months post-treatment (T3), 9 months post-treatment (T4) and 12 months post-treatment (T5).
- Conditions
- Overweight or Obesity, Chronic Low-back Pain
- Being tested
- Physiotherapy intervention, including behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy., Physiotherapy intervention, including pain neuroscience education and cognition-targeted exercise therapy alone.
- Medical subject headings
- Overweight, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Physiotherapy intervention, including behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy.Behavioural
Also called EXP (Experimental intervention)
14 weeks, 18 treatment sessions
This includes:
- 3 sessions of Pain Neuroscience Education during the first two weeks (of which the second one will be held online). The aim is to to reconceptualize pain, to increase pain coping skills and to convince the patients that pain is in the brain, and that hypersensitivity of the central nervous system rather than local tissue damage contributes to their symptoms.
- 15 sessions which will focus simultaneously on cognition-targeted exercise therapy and behavioral weight reduction. The aim of the exercise program is to confront the patient with movements and activities that are feared, avoided and/or painful. The behavioral weight reduction program includes a lifestyle approach, with changes in diet, behavior, and a physical exercise weight loss program, all aiming for a caloric deficit of 500 to 700 kcal/day.
Physiotherapy intervention, including pain neuroscience education and cognition-targeted exercise therapy alone.Behavioural
Also called CON (Control intervention)
14 weeks, 18 treatment sessions
This includes:
- 3 sessions of Pain Neuroscience Education during the first two weeks (of which the second one will be held online). The aim is to to reconceptualize pain, to increase pain coping skills and to convince the patients that pain is in the brain, and that hypersensitivity of the central nervous system rather than local tissue damage contributes to their symptoms.
- 15 sessions which will only focus on cognition-targeted exercise therapy. The aim of the exercise program is to confront the patient with movements and activities that are feared, avoided and/or painful.
| Study group | Role | What they receive |
|---|---|---|
| Experimental Intervention | Experimental | Physiotherapy intervention, including behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy. Receives: Behavioral: Physiotherapy intervention, including behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy. |
| Control Intervention | Active comparator | Physiotherapy intervention, including pain neuroscience education and cognition-targeted exercise therapy alone. Receives: Behavioral: Physiotherapy intervention, including pain neuroscience education and cognition-targeted exercise therapy alone. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Brief Pain Inventory - Average pain Intensity
Since CLBP is a fluctuating condition, the question "please rate your pain by circling the one number that best describes your pain on the AVERAGE" is used as primary outcome measure to evaluate pain intensity. The answer to this question is formulated on an 11-point (i.e., 0-10, a decrease of 30% is considered as clinically significant) numeric rating scale (NRS). Higher scores indicate higher pain intensity.
Measured: Change from baseline to 12 months post-intervention
Secondary outcomes (19)
Brief Pain Inventory - Pain intensity (Average, worst, least, now)
The BPI will also be used to assess pain intensity at other timepoints.
Measured: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Brief Pain Inventory - Pain interference on functioning
The BPI also evaluates the impact of pain on functioning. The BPI measures how much pain interferes with seven daily activities, including general activity, walking, work, mood, enjoyment of life, relations with others, and sleep on an 11-point NRS (ranging from 0-10). Higher scores indicate a bigger interference of pain with activities of daily life.
Measured: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Pain distribution and pain extent by pain drawings
Extent of pain will be indicated by the participants making use of a digital pain drawing obtained using a digital tablet and commercially available sketching software
Measured: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Tampa Scale for Kinesiophobia (TSK)
The TSK contains questions about pain-related fear of movement, fear of (re)injury and fear avoidance behavior. The TSK results in a score ranging from 17 to 68, where higher scores indicate an increasing degree of kinesiophobia.
Measured: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Fear Avoidance Belief Questionnaire
The fear avoidance belief questionnaire focuses on LBP patient's beliefs about how physical activity and work affect LBP (fear of pain caused by physical activity). This questionnaire results in a total score (ranging from 0 to 96) and two subscale scores: work subscale (ranges from 0 to 42) and physical activity subscale (score 0 to 24). Higher scores indicate more strongly held fear avoidance beliefs.
Measured: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Body weight - Tanita
Body weight (kg) will be measured using TANITA MC-780SMA Bio-electrical Impedance Analyzer.
Measured: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
BMI - Tanita
BMI will be measured using TANITA MC-780SMA Bio-electrical Impedance Analyzer.
Measured: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Fat mass - Tanita
Fat mass will be measured using TANITA MC-780SMA Bio-electrical Impedance Analyzer.
Measured: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Fat free mass - Tanita
Fat free mass will be measured using TANITA MC-780SMA Bio-electrical Impedance Analyzer.
Measured: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Muscle mass - Tanita
Muscle mass will be measured using TANITA MC-780SMA Bio-electrical Impedance Analyzer.
Measured: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Body Water - Tanita
Body water will be measured using TANITA MC-780SMA Bio-electrical Impedance Analyzer.
Measured: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Waist-hip circumference
Measured using a Cescorf measuring tape,
Measured: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Regional body composition - portable ultrasound scanner
Subcutaneous adipose tissue thickness of the triceps, biceps, subscapular, iliac crest, supraspinal, abdominal and medial calf will be assessed. Additionally, muscle thickness of the multifidi will be assessed.
Measured: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Accelerometry Fitbit
To objectively measure sedentary behavior, physical activity and sleep quantity/quality
Measured: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Sleep Quality - Pittsburg Sleep Quality Index
Questionnaire assessing Sleep Quality. In scoring the PSQI, seven component scores are derived, each scored 0 (no difficulty) to 3 (severe difficulty). The component scores are summed to produce a global score (range 0 to 21). Higher scores indicate worse sleep quality.
Measured: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Dietary Intake
a 3 day food diary, 2 week days and 1 weekend day, will be used to analyse their dietary intake.
Measured: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Health Economics - Medical Consumption Questionnaire
a generic instrument for measuring patient's total direct and indirect medical consumption. For this type of questionnaire and the aspect it is measuring, we cannot refer to minimum or maximum values.
Measured: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment, 9 months post-treatment and 12 months past-treatment
Health Economics - Productivity Cost Questionnaire
to obtain data regarding the indirect medical costs (e.g., the costs due to absenteeism or presenteeism). For this type of questionnaire and the aspect it is measuring, we cannot refer to minimum or maximum values.
Measured: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment, 9 months post-treatment and 12 months past-treatment
Health Economics - EuroQol EQ-5D-5L
to assess health profiles which will be transformed into utilities using the Flemish or German Tariffs respectively. For this type of questionnaire and the aspect it is measuring, we cannot refer to minimum or maximum values.
Measured: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment, 9 months post-treatment and 12 months past-treatment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Apr 2023
- Study start13 Apr 2023
- Primary completionApr 2028 (estimated)
- Study completionNov 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Overweight or ObesityStudies of the same condition, open and under way.
- More trials run by Vrije Universiteit BrusselThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Study participants will be randomized (1/1) into one of the two treatment arms (control or intervention)
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 252 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Vrije Universiteit Brussel
- Sponsor type
- University, hospital or other
- Collaborators
- Bern University of Applied Sciences, University of Applied Sciences and Arts of Southern Switzerland
- Responsible party
- Principal investigator, Jo Nijs, Vrije Universiteit Brussel
- Investigators
- Jo Nijs, PhD, Principal investigator, Vrije Universiteit Brussel
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05811624
- Sponsor's protocol ID
- BUN1432022000296
- Other IDs
- G094322N, 2022-02210, S011866-42-PHYW
- Acronym
- BO2WL
- Status last verified
- Aug 2026
- First submitted
- 14 Mar 2023
- Last updated
- 20 Aug 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: We do not plan to share any IPD
Publications
Schurz AP, Lutz N, Liechti M, Malfliet A, Vanroose M, Maebe Z, Nijs J, Van Bogaert W, Clarys P, Clijsen R, Baur H, Taeymans J, Deliens T. Cost of illness analysis in individuals with overweight or obesity and chronic low back pain in the Bern metropolitan area (the BO2WL trial). Front Public Health. 2026 Jan 13;13:1705891. doi: 10.3389/fpubh.2025.1705891. eCollection 2025.
PubMed 41607914Schurz AP, Deliens T, Liechti M, Vanroose M, Clijsen R, Nijs J, Malfliet A, Van Bogaert W, Clarys P, Baur H, Taeymans J, Lutz N. Economic evaluation of a lifestyle intervention for individuals with overweight or obesity suffering from chronic low back pain (the BO2WL trial): a protocol for a health economic analysis. BMJ Open. 2025 Jun 20;15(6):e098272. doi: 10.1136/bmjopen-2024-098272.
PubMed 40541436
Study at a glance
From the registry record, last updated by the sponsor on 20 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Lifestyle Intervention in Overweight/Obese People Suffering From Chronic Low Back Pain: an International Multi-center Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT05811624
- Acronym / sponsor ID
- BO2WL / BUN1432022000296
- Conditions
- Overweight or Obesity, Chronic Low-back Pain
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 252 participants (estimated)
- Lead sponsor
- Vrije Universiteit BrusselUniversity, hospital or other
- Collaborators
- Bern University of Applied Sciences, University of Applied Sciences and Arts of Southern Switzerland
- Study start
- 13 Apr 2023 (actual)
- Primary completion
- Apr 2028 (estimated)
- Study completion
- Nov 2028 (estimated)
- First posted
- 13 Apr 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Chronic low back pain (CLBP) is the most expensive cause of workrelated disability: it causes the highest number of years lived with disability. The most severe and debilitated CLBP patients often have comorbidities such as overweight and obesity. Despite the growing body of scientific literature pointing towards the close interaction between overweight/obesity and CLBP, few treatment programs for people with CLBP nowadays take overweight into account. Therefore this study will examine the added value of a behavioral weight reduction program (changes in diet, behavior and physical exercise) to current best evidence rehabilitation (pain neuroscience education plus cognition-targeted exercise therapy) for overweight or obese people with CLBP. An international, multicenter randomized controlled trial comparing a behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy versus pain neuroscience education and cognition-targeted exercise therapy alone, will be conducted. The primary outcome is pain and the primary endpoint was chosen at 12 months follow-up; secondary outcomes include health care use and daily functioning (see detailed description of outcomes for an overview of all secondary outcomes). If the promising results of the proof of concept study are corroborated, the new intervention will have a high socio-economic impact, including an annual health care cost reduction of €66 million in Switzerland, and €60 million in Flanders, and is expected to increase life expectancy in the long term.
Detailed description
Rationale:
Chronic low back pain (CLBP) is the most common and important clinical, social, economic, and public health problem of all chronic pain disorders across the world. In addition to its high prevalence, CLBP is a severely disabling disorder characterized by tremendous personal and socioeconomic impact. Furthermore, it is the most common cause of work-related disability, generating long-term sick-leaves, and it causes the highest number of years lived with disability.
The most severe and debilitated CLBP patients often have comorbidities such as overweight and obesity. In fact, pain intensity and disability in people with CLBP show dose-responses to body mass index (BMI), waist circumference, percent fat and fat mass. Ample studies and several meta-analyses indeed confirm that overweight and obesity are associated with LBP, with overweight and obesity even being a risk factors for low back pain. Regarding socio-economic impact, overweight or obesity is not only related to LBP persistence, but also to higher rates of health care seeking for LBP. Obviously, people with CLBP who are overweight or obese, are likely to have more complex health needs requiring focus on lifestyle behavioral factors such as physical activity/exercise and diet.
CLBP is a complex disorder which is difficult to treat. Exercise therapy is an evidence-based treatment for CLBP both general exercises and cognition-targeted exercise therapy have shown beneficial effects on pain in patients with CLBP. Unfortunately, current treatments for CLBP apply a 'one-size-fits-all' approach and do not address comorbidities like obesity. This knowledge gap is now acknowledged internationally: overweight and obesity are increasingly recognized as a plausible therapeutic target for people with CLBP. Despite the growing body of scientific literature pointing towards the close interaction between overweight/obesity and CLBP few treatment programs for people with CLBP nowadays take overweight into account.
Few studies explored the added value of weight reduction to the management of people with CLBP. Yet, proof of concept for combining dietary changes with exercise therapy for patients with CLBP and comorbid overweight/obesity show promising results. Here we propose studying the added value of a behavioral weight reduction program (changes in diet, behavior, and physical exercise) to blended rehabilitation (PNE plus CTET) for overweight or obese people with CLBP. Both treatments are effective in their specific target population (i.e., behavioral weight reduction for overweight/obese people and PNE plus CTET for people with CLBP and normal BMI), but whether their combined approach is cumulative in overweight/obese people with CLBP is currently unknown and represents an important research priority.
Objectives:
The primary objective is to examine if a behavioral weight reduction program combined with Pain Neuroscience Education (PNE) and Cognition-Targeted Exercise Therapy (CTET) is superior to reduce pain at 12 months follow-up compared PNE and CTET alone, in overweight or obese people with CLBP.
Secondary objectives are to examine the effects of adding a behavioral weight reduction program combined with PNE and CTET, compared to PNE and CTET alone, on 1) other pain related outcomes (pain interference, pain distribution and pain beliefs), 2) on anthropometrics (body weight/composition, muscle thickness and fat distribution), 3) on energy balance related behavior (24h continuous activity monitoring, dietary intake and sleep) and finally 4) on health economics (heath care utilization, productivity loss and quality of life) at 12 months follow-up.
Interventions:
Both interventions (experimental and control) are organized equally: all participants will receive 18 treatment sessions over a 14-week period see table 2 for a detailed overview. Rather than practical, treatment arms will differ in content.
The control intervention will consist of a total of 18 treatment sessions distributed over 14 weeks. It comprises of only the chronic-pain-focused interventions: 3 sessions of PNE in the first 2 weeks \& secondly, 15 sessions of CTET in the remaining 12 weeks.
The experimental intervention will consist of a total of 18 treatment sessions distributed over 14 weeks. The first part will consist of chronic-pain-focused interventions: firstly, 3 sessions of PNE in the first 2 weeks \& secondly, 15 sessions of CTET in the remaining 12 weeks. The second part will consist of a more weight-reduction-focused intervention. The weight reduction intervention is a lifestyle approach that will be integrated in the CTET intervention, implying that grading daily physical activity and exercise levels will aim at reducing weight (i.e. together with a change in diet we aim at a caloric deficit of 500 to 700 kcal/day) and improving pain cognitions at the same time.
Study design:
Randomized controlled trial with follow-up assessments directly post-treatment (T1), 3 months post-treatment (T2), 6 months post-treatment (T3), 9 months post-treatment (T4) and 12 months post-treatment (T5).
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Study participants will be randomized (1/1) into one of the two treatment arms (control or intervention)
| Arm | Type | Receives |
|---|---|---|
| Experimental Intervention | Experimental | Behavioral: Physiotherapy intervention, including behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy.Physiotherapy intervention, including behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy. |
| Control Intervention | Active comparator | Behavioral: Physiotherapy intervention, including pain neuroscience education and cognition-targeted exercise therapy alone.Physiotherapy intervention, including pain neuroscience education and cognition-targeted exercise therapy alone. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Adults (18 - 65 years)
- Overweight (BMI ≥ 25 kg/m2) or obese (BMI ≥ 30 kg/m2) women and men.
- CLBP (n=252), which is defined as nonspecific low back pain for at least 3 months duration, currently seeking care for low back pain and leg pain not ≥ 7 (on a maximum of 10) on a numeric rating scale.
- Continue usual care 6 weeks prior to (to obtain a steady stat) and during study participation.
- Depending on the country of inclusion: Native Dutch speaker (for Belgium) or Native German speaker (for Switzerland).
Key exclusion criteria (6 listed)
- Patients with BMI ≥ 40 kg/m² will be excluded as people being morbid obese are eligible to undergo abdominal surgery. Because BMI may not always correspond to the same body fat percentage in different individuals (e.g., athletic types with higher muscle mass may also have BMIs ≥ 25 km/kg²), each participant's body fat percentage will be measured using the TANITA and compared to the body fat percentage reference values. Participants with exceeding BMI but falling into the healthy fat percentage range (which is sex-, age- and ethnicity dependent will be excluded.
- Pregnant, currently breastfeeding or given birth in preceding year.
- Currently receiving dietary or exercise interventions or received in the past 6 weeks.
- Show evidence of specific spinal pathology based on self-report (e.g., hernia, spi-nal stenosis, spondylolisthesis, infection, spinal fracture or malignancy), or a se-vere underlying comorbidity specific diagnoses that interfere with treatment (e.g., diagnosed diabetes, cardiovascular problems, metabolic diseases)
- Other severe diseases based on current medication intake or being currently treated by a medical doctor for a specific diagnosis, (e.g. diagnosed eating disorders).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Physiotherapy intervention, including behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy.Also: EXP (Experimental intervention)14 weeks, 18 treatment sessions This includes: * 3 sessions of Pain Neuroscience Education during the first two weeks (of which the second one will be held online). The aim is to to reconceptualize pain, to increase pain coping skills and to convince the patients that pain is in the brain, and that hypersensitivity of the central nervous system rather than local tissue damage contributes to their symptoms. * 15 sessions which will focus simultaneously on cognition-targeted exercise therapy and behavioral weight reduction. The aim of the exercise program is to confront the patient with movements and activities that are feared, avoided and/or painful. The behavioral weight reduction program includes a lifestyle approach, with changes in diet, behavior, and a physical exercise weight loss program, all aiming for a caloric deficit of 500 to 700 kcal/day. | Behavioural | Experimental Intervention |
| Physiotherapy intervention, including pain neuroscience education and cognition-targeted exercise therapy alone.Also: CON (Control intervention)14 weeks, 18 treatment sessions This includes: * 3 sessions of Pain Neuroscience Education during the first two weeks (of which the second one will be held online). The aim is to to reconceptualize pain, to increase pain coping skills and to convince the patients that pain is in the brain, and that hypersensitivity of the central nervous system rather than local tissue damage contributes to their symptoms. * 15 sessions which will only focus on cognition-targeted exercise therapy. The aim of the exercise program is to confront the patient with movements and activities that are feared, avoided and/or painful. | Behavioural | Control Intervention |
Primary outcome
Brief Pain Inventory - Average pain Intensity
Time frame: Change from baseline to 12 months post-intervention
Since CLBP is a fluctuating condition, the question "please rate your pain by circling the one number that best describes your pain on the AVERAGE" is used as primary outcome measure to evaluate pain intensity. The answer to this question is formulated on an 11-point (i.e., 0-10, a decrease of 30% is considered as clinically significant) numeric rating scale (NRS). Higher scores indicate higher pain intensity.
19 secondary outcomes
Brief Pain Inventory - Pain intensity (Average, worst, least, now)
Time frame: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Brief Pain Inventory - Pain interference on functioning
Time frame: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Pain distribution and pain extent by pain drawings
Time frame: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Tampa Scale for Kinesiophobia (TSK)
Time frame: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Fear Avoidance Belief Questionnaire
Time frame: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Body weight - Tanita
Time frame: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
BMI - Tanita
Time frame: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Fat mass - Tanita
Time frame: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Fat free mass - Tanita
Time frame: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Muscle mass - Tanita
Time frame: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Body Water - Tanita
Time frame: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Waist-hip circumference
Time frame: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Regional body composition - portable ultrasound scanner
Time frame: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Accelerometry Fitbit
Time frame: This outcome will be assessed at Baseline, directly post-treatment, and 12 months past-treatment
Sleep Quality - Pittsburg Sleep Quality Index
Time frame: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Dietary Intake
Time frame: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment and 12 months past-treatment
Health Economics - Medical Consumption Questionnaire
Time frame: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment, 9 months post-treatment and 12 months past-treatment
Health Economics - Productivity Cost Questionnaire
Time frame: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment, 9 months post-treatment and 12 months past-treatment
Health Economics - EuroQol EQ-5D-5L
Time frame: This outcome will be assessed at Baseline, directly post-treatment, 3 months post-treatment, 6 months post-treatment, 9 months post-treatment and 12 months past-treatment
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Aug 2026.
- Derived from this study: PubMed 41607914Schurz AP, Lutz N, Liechti M, Malfliet A, Vanroose M, Maebe Z, Nijs J, Van Bogaert W, Clarys P, Clijsen R, Baur H, Taeymans J, Deliens T. Cost of illness analysis in individuals with overweight or obesity and chronic low back pain in the Bern metropolitan area (the BO2WL trial). Front Public Health. 2026 Jan 13;13:1705891. doi: 10.3389/fpubh.2025.1705891. eCollection 2025.
- Derived from this study: PubMed 40541436Schurz AP, Deliens T, Liechti M, Vanroose M, Clijsen R, Nijs J, Malfliet A, Van Bogaert W, Clarys P, Baur H, Taeymans J, Lutz N. Economic evaluation of a lifestyle intervention for individuals with overweight or obesity suffering from chronic low back pain (the BO2WL trial): a protocol for a health economic analysis. BMJ Open. 2025 Jun 20;15(6):e098272. doi: 10.1136/bmjopen-2024-098272.
- Individual participant dataSharing planned: No. We do not plan to share any IPD
Related trials for Overweight or Obesity
Not yet recruitingPhase 3
A Study to Evaluate the Effectiveness and Safety of the Drug AZD6234 for Managing Weight in Adults Who Are Obese or Overweight. These Participants May or May Not Also Have Type 2 Diabetes
Obesity, Overweight
RecruitingPhase 3
Efficacy, Safety and Tolerability of Switching From Glucagon-like Peptide-1 Receptor Agonists (GLP-1RA) to Maridebart Cafraglutide in Adults With Obesity or Overweight (MARITIME-SWITCH)
Obesity or Overweight
RecruitingPhase 1
A Study to Learn How Different Forms of the Study Medicine Called Berobenatide is Taken up Into the Blood in Adults With Overweight or Obesity
Overweight and/or Obesity, Healthy Participants
RecruitingPhase 2
Study of Olatorepatide in Adult Participants Living With Overweight or Obesity Without Diabetes
Overweight or Obesity
Active, not recruitingPhase 3
AMAZE 2: A Research Study Investigating How Well the Medicine NNC0487-0111 Helps People With Excess Body Weight and Type 2 Diabetes Lose Weight
Diabetes Mellitus, Overweight
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Jo Nijs, PhD contact
Jo Nijs, PhD principal investigator
Vrije Universiteit Brussel
2 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Physiotherapy intervention, including behavioral weight reduction program combined with pain neuroscience education and cognition-targeted exercise therapy. and Physiotherapy intervention, including pain neuroscience education and cognition-targeted exercise therapy alone. in people with Overweight or Obesity and Chronic Low-back Pain, run by Vrije Universiteit Brussel at 2 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 20 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Belgium, Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Anneleen Malfliet, PhD (003224774531, anneleen.malfliet@vub.be), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Brief Pain Inventory - Average pain Intensity (time frame: Change from baseline to 12 months post-intervention). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05811624, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Aug 2026.