Addressing co-occurring chronic pain and obesity simultaneously in a behavioral intervention: a pilot trial

Abstract

Background

Chronic musculoskeletal pain and overweight/obesity are comorbid conditions that negatively impact each other, yet interventions targeting this comorbidity are limited. This study evaluated the feasibility and acceptability of an integrated weight and pain management intervention that uniquely targets environmental reward processes and positive affect.

Methods

Participants (45–80 years) with comorbid overweight/obesity (BMI ≥ 25 kg/m²) and moderate-to-high impact musculoskeletal pain participated in a single-arm trial of a remotely delivered intervention integrating behavioral weight loss treatment and cognitive-behavioral pain coping therapy addressing mechanisms of environmental reward and positive affect. Assessments of weight, pain (via PROMIS pain intensity, interference, and physical function scales; Short Physical Performance Battery), and process variables were completed at baseline, 4 months (end of core intervention phase), and 8 months (end of elective intervention phase). Recruitment and retention metrics and patient satisfaction ratings were measured.

Results

Thirty-three patients enrolled in the trial. Of these, 76% (n = 25) completed the core intervention and 79% (n = 26) completed the 4-month assessment. Results indicated high credibility (7.8/10) and session engagement (6.7/8), and global treatment satisfaction (3.6/4) was high. At 4 months, pain impact decreased by 4.0 points from pre- to post-intervention and mean weight loss was 2.4% of baseline body weight, with n = 4 participants (15.4%) achieving ≥ 5% weight loss. Of the 19 participants who completed the elective phase, pain impact decreased from baseline by 6.6 points and mean weight loss percent from baseline was 3.0%.

Conclusions

Overall, this pilot study demonstrated that a remotely delivered weight loss plus pain reduction intervention is feasible and was well accepted by participants with overweight/obesity and comorbid pain. The intervention produced reductions in pain and weight, supporting further testing in a fully powered clinical trial.

Trial registration

This trial is registered in ClinicalTrials.gov (NCT04851587).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-026-01764-3.

Key messages regarding feasibility

• The trial feasibility and acceptability of an intervention addressing pain and obesity simultaneously while incorporating a focus on meaningful and rewarding activities is unknown.

• Recruitment and retention data suggest the feasibility of the trial approach; the intervention had overall good acceptability; and clinically meaningful changes in pain and physical functioning were found, while effects on body weight were smaller than targeted.

• Additional refinement of the intervention is warranted to enhance weight loss outcomes and further increase engagement in meaningful and rewarding activities.

Background

Chronic pain is the leading cause of disability worldwide, affecting 1 in 4 adults ages 45 and older in the USA [1]. Similar or higher prevalence rates are reported in Europe, China, and many other nations [2]. Chronic pain negatively impacts mental health, mobility, social functioning, and independent living [3], with musculoskeletal pain in the back, knees, and hips among the most common conditions [4].

Chronic pain is highly comorbid with obesity and overweight, affecting over 70% of Americans [5]. Globally, 1 in 8 people meet criteria for obesity (body mass index (BMI) ≥ 30 kg/m²) and nearly half qualify as overweight (BMI ≥ 25 kg/m²) [6, 7]. Excess weight is linked to cardiovascular and metabolic diseases, poor mental health, lower quality of life, and mortality [8–11]. Individuals with overweight or obesity have up to a 43% higher risk of chronic low back pain compared to adults with a BMI < 25 kg/m² [12]. This comorbidity further increases the risk of disability, depression, and opioid use [13–15], as well as cardiovascular disease, sleep disorders, cognitive impairment, and mortality [14, 16–20].

Prospective observational studies suggest a bidirectional relationship between pain and weight, with pain contributing to weight gain and vice versa. For example, in a cohort of individuals receiving workers’ compensation after a back injury (n = 1263), 14% had gained ≥ 7% of their initial body weight 1 year post-injury [21], while in a Norwegian population-based cohort (n = 4496) [22], obesity was associated with 40% greater odds of developing chronic back pain. Given this association, addressing obesity can be particularly challenging in the presence of chronic pain, and pain management efforts may be less effective if the impact of excess weight is overlooked.

In light of this relationship, interventions targeting pain and obesity simultaneously may yield more optimal outcomes. Behavioral interventions have been effective in promoting weight loss and improving pain coping [23–25]; however, few studies have explicitly targeted both simultaneously. Preliminary evidence from pilot studies in breast cancer patients and their partners, as well as in rheumatoid arthritis, suggests that integrated approaches addressing both pain and weight are feasible and beneficial, with reductions in weight and improvements in function, pain, and self-efficacy observed [26, 27]. Moreover, Somers et al. [28] found that patients with osteoarthritis receiving integrated pain and weight loss treatment had greater reductions in pain severity (43%), disability (41%), and weight (5%) compared to individuals given pain or weight-focused interventions alone.

Building on this work, we developed EMPOWER (Empowering the Management of Pain-Obesity-Weight through Enhanced Reward), a behavioral intervention designed to concurrently address overweight/obesity and chronic pain. Alongside standard approaches targeting skills training for pain management and weight loss, EMPOWER targets key factors proposed to maintain both conditions: environmental reward deprivation and decreased positive affect. As illustrated in our conceptual model (Fig. 1), chronic pain (whether from injury or other precipitants) results in environmental reward deprivation, which occurs when chronic pain diminishes the reward value of activities, leading to reduced enjoyment in and withdrawal from pleasurable and meaningful activities [29, 30]. This withdrawal is often exacerbated by an overgeneralized fear of pain, consistent with the “fear avoidance model” of pain [31, 32].

Fig. 1.

Conceptual model of the bidirectional relationship between chronic pain and weight including proposed mechanisms underlying the association

Both reward deprivation and pain contribute to reductions in positive affect [33], which in turn drives excess food intake and reduced physical activity. When non-food rewards are limited due to chronic pain, high-calorie foods may become more reinforcing and increase caloric intake—a concept supported by behavior choice theory, which posits that engagement with a reinforcer (e.g., food) increases in the absence of alternative reinforcers [34]. Consistent with this, studies show that adults with obesity engage less in non-food-related pleasant activities [35, 36], and individuals with chronic pain report that eating is a source of pleasure when activities are restricted due to pain [37].

Low positive affect may further contribute to excess food intake when eating is used to improve mood and distract from pain [37, 38]. Additionally, low positive affect may reduce engagement in physical activity [39]. The combination of increased food intake and inactivity leads to weight gain, which exacerbates pain via joint loading, biochemical mediators, and inflammation [14, 40, 41]. In turn, increased pain reinforces weight gain, creating a negative feedback loop that perpetuates both conditions. Excess weight can also impose additional activity limitations, further restricting access to rewarding experiences and sustaining the cycle of pain and weight gain [42–44].

To address the factors outlined in our conceptual model, EMPOWER integrates traditional pain coping and behavioral weight loss skills with strategies that foster engagement in pleasant activities and values-based content. This study aimed to pilot test the EMPOWER intervention to assess its acceptability, potential impact, and the feasibility of the trial procedures.

Methods

Study design and participants

This single-arm trial tested the EMPOWER intervention, which included a 4-month core phase followed by a 4-month elective phase. Assessments occurred at baseline, 4 months, and 8 months (Trial Registration: NCT04851587; Date: April 1, 2021). Enrollment occurred from September 2021 to January 2023. Participants were adults aged 45 to 80 years with a body mass index (BMI) ≥ 25 kg/m² who had chronic musculoskeletal pain in their lower back region, knees, or hips. Additional eligibility criteria are shown in Table 1.

Table 1.

Eligibility criteria

Inclusion criteria
• Body Mass Index (BMI) ≥ 25 kg/m2 • Aged 45 to 80 years • Chronic musculoskeletal pain in lower back region, knees, or hips • Pain severity reported at ≥ 3 on a 0 to 10 numeric rating scale • Pain occurring on at least 50% of days in the prior six months • Pain having, at minimum, a moderate impact on life (≥ 28 on the Research Task Force Impact Stratification Scale)
Exclusion criteria
• Chronic, malignant pain (e.g., cancer) or systemic inflammatory disease (e.g., rheumatoid arthritis) • Back, knee, or hip surgery in the prior 6 months • Bariatric surgery in the past year • Current use of weight loss medications • Pregnant or breastfeeding • Currently enrolled in another psychological treatment or structured weight loss program • Uncontrolled psychiatric illness • Significant cognitive impairment • Unable to read/write in English • Undergoing radiation or chemotherapy for cancer • Recent cardiac event • Blood pressure higher than 180/100 mmHg

Recruitment and enrollment

Participants were recruited using various methods, including an electronic search of the University of Florida (UF) Health System’s administrative and clinical (Electronic Health Record) database identifying patients with elevated BMI (based on recorded height and weight) and documented musculoskeletal pain (based on ICD-10 codes). The specific ICD-10 codes used to define musculoskeletal pain are provided in Supplementary File 1. Additionally direct outreach at a UF specialty spine clinic and provider referrals were used. Recruitment took place at UF Health in Gainesville and Jacksonville, Florida (United States of America [USA]).

After a phone screening, participants attended an in-person screening/baseline session where informed consent was reviewed and additional eligibility criteria (e.g., blood pressure, cognitive impairment) were assessed. Following the baseline appointment, participants were scheduled for their first intervention group session. Ethics approval was provided by the UF Institutional Review Board (IRB202002133) and all participants provided informed consent prior to study procedures.

Intervention protocol

The EMPOWER 4-month core phase included eight 1.5-h group sessions (biweekly) and eight 30-min individual calls occurring in alternating weeks when a group was not offered. Groups were led by a trained health behavioral interventionist, who also conducted individual phone calls. The 4-month elective phase included eight 1.5-h group sessions without individual phone calls. Core and elective sessions were delivered via Zoom. A remote delivery approach was initially selected to address concerns about COVID-19 transmission but was retained due to high participant satisfaction with this format. Although the intervention was originally designed as an 8-month program, a phased structure (i.e., core and elective modules) was introduced during early enrollment to enhance recruitment, as individuals were more likely to commit to a 4-month intervention than a full 8-month program. Over the course of the study, the team implemented additional refinements to strengthen engagement and data quality such as adopting a more intensive and standardized approach to contacting participants for assessments, improving monitoring of questionnaire completion and goal-setting activities, and offering greater flexibility for scheduling and completing makeup sessions.

EMPOWER integrated traditional pain coping and behavioral weight loss strategies, as well as components focused on reward and positive affect (Table 2). The pain management components were drawn from empirically supported pain management protocols such as cognitive-behavioral therapy (CBT) and acceptance and commitment therapy (ACT) [45, 46]. Pain and weight management content were incorporated into the group sessions with equal emphasis placed on both areas within the same sessions when possible. The weight management components were closely adapted from the Diabetes Prevention Program (DPP) protocol [47, 48], recognized as a gold standard in weight loss interventions [49, 50]. Participants were assigned a goal of losing 5–7% of baseline weight over the 8-month intervention (500 kcal daily deficit) and given recommendations for dietary intake based on the American Heart Association guidelines (e.g., emphasis on whole grains, limitation of saturated fat). Participants were asked to monitor their daily food intake via a commercial app or paper and pen. Also consistent with the DPP, there was a focus on increasing moderate-to-vigorous physical activity [47].

Table 2.

Intervention session content

Session	Title	Content
Core modules
1	Introduction and Overview	• Symptoms and causes of pain • Dietary tracking and weight loss goals • Overlap of pain and weight
2	Pleasant Activity Scheduling and Values	• Benefits of pleasant activities • Identifying and clarifying values • Setting and achieving attainable goals
3	Physical Activity and Time-Based Activity Pacing	• Benefits of physical activity • Identifying ways to become active • Pacing activity to minimize pain
4	Healthy Eating and Physical Activity	• Purpose of tracking activity and food • Building a healthy meal • Link between calories and weight
5	Taking Charge of Pain and Weight Thoughts	• Role of thoughts in pain and weight • Identify automatic thoughts • Ways to reframe negative situations
6	Stress Management and Relaxation Training	• Relationship between stress and health • Purpose of stress management • Practice of relaxation techniques
7	Getting Support to Manage Pain and Lose Weight	• Benefits of supportive relationships • Ways to obtain support from others
8	Coping with Pain and Triggers for Overeating	• Triggers for overeating, skipping exercise, and pain flares • Coping with triggers
Elective modules
9	Eating Well by Buying and Preparing Healthy Food	• Importance of meal planning • Shopping for healthy food • Building a healthy meal
10	Mindfulness for Pain and Dietary Change	• Mindfulness for pain and weight • Practice of mindfulness techniques
11	Increasing Physical Activity and Overcoming Barriers	• Health benefits of physical activity • Barriers to physical activity • Staying motivated and reducing boredom
12	Communication and Time Management	• Link between stress, weight, and pain • Assertive communication • Time management
13	Self-Acceptance Strategies for Weight and Pain	• Role of willingness in weight management • Addressing food urges
14	Improving Sleep to Help with Pain and Weight Management	• Importance of sleep in pain and weight • Factors contributing to sleep disturbance • Methods to promote better sleep
15	Eating Well Away from Home and Heart-Healthy Eating	• Barriers to eating well away from home • Managing barriers to eating well • Heart healthy activities
16	Staying Motivated and Preventing Relapse	• Review of program progress • Relapse prevention

To enhance environmental reinforcement and positive affect, two of the group sessions focused on engagement in rewarding and valued activities, while individual phone sessions included pleasant activity scheduling and values-based goal setting. For example, participants identified enjoyable or meaningful activities (e.g., taking a short walk outdoors, engaging in a hobby) and linked them to their core values (e.g., spending time with family, enriching their knowledge). Participants then set S.M.A.R.T. (i.e., specific, measurable, achievable, relevant, time-bound) goals, evaluated prior goal progress, and problem-solved barriers to meeting goals. To encourage exposure to a variety of potentially reinforcing activities and to increase overall physical activity levels, participants selected at least one goal from each of three categories: a social activity (e.g., spending time with family), a cognitively enriching activity (e.g., puzzles, meditation), and an activity involving at least a moderate level of physical exertion. Participants selected two goals each week, always including a physical activity goal and rotating the other two categories, which were then tracked independently using their preferred method (e.g., paper log, app). Progress was reviewed during their subsequent individual session, and information regarding participant goals was recorded in REDCap. To accommodate pain, each participant worked with their interventionist to set individualized goals tailored to their specific limitations.

Treatment fidelity

The intervention was manualized and included interventionist and participant workbooks. Interventionists were graduate students and health professionals trained and supervised by the study investigators (MM, EB) who received extensive didactic and experiential training from the study PI’s prior to delivering the program to standardize intervention delivery.

Measures

Individual patient assessments were conducted in person at baseline, 4-month, and 8-month time points. All self-report measures were completed either online via REDCap survey software or on paper, depending on participant preference. Secondary outcome and process measures were conducted at all study time points. Specific, pre-defined thresholds for proceeding to a future trial are shown in Table 3. Participants were compensated $15 for the completion of each intervention session and $30 for each in-person assessment.

Table 3.

Metrics of success and outcome summary

Variable	Pre-specified benchmark for success	Outcome
Session-level engagement	≥ 6 mean score (0–8 point scale)	Core sessions: mean = 6.4; Optional sessions: mean = 6.9: Benchmark met
Global treatment engagement	≥ 80% attendance at sessions overall, and ≥ 70 attendance at both group and phone sessions considered separately	79.9% attendance during core sessions among all enrollees: Benchmark not met; 81.4% attendance during core group sessions and 78.4% attendance during core individual sessions among all enrollees: Benchmark met; 94–96% attendance among intervention completers; Benchmark met
Participant satisfaction	≥ 3 mean score (on 1–4 point scale)	Core: mean = 3.5; Optional: mean = 3.7: Benchmark met
Treatment credibility	≥ 7 mean score (0–10 point scale)	mean = 7.8: Benchmark met
Recruitment rate	≥ 2.5 participants enrolled per week during active recruitment	33 participants enrolled over 16 months: Benchmark not met
Retention at assessments	By the last two cohorts, ≥ 80% who enroll complete the 8-month assessment	80% retained at final assessment in last two cohorts: Benchmark met

Feasibility and acceptability outcomes

Feasibility of the intervention

Data were collected on the number of participants enrolled in study procedures, retention at the 4- and 8-month assessments, and the number of intervention sessions completed.

Session-level engagement

Treatment engagement questions were developed to assess participants’ effort in group activities and participation in discussions (e.g., “How interested were you in the material presented in today’s session;” “How involved were you in the discussions in today’s session”). This 5-item questionnaire was completed by each participant at the end of each session. Items are rated on a 9-point Likert scale ranging from 0 (none) to 8 (a lot). A mean score was computed across sessions (mean α core sessions = 0.91, mean α optional sessions = 0.94).

Treatment credibility

Treatment credibility questions were developed [51] and administered during the baseline visit, and consisted of seven items rated on an 11-point Likert scale. Questions addressed reasonableness of the intervention, willingness to undergo treatment, and confidence in the program. Mean values were calculated, with higher scores indicating greater treatment credibility (α = 0.80).

Treatment satisfaction

A single treatment satisfaction item (“In an overall, general sense, how satisfied are you with the intervention program you received?”) was administered at 4- and 8-month assessments. This item was rated on a 4-point Likert scale ranging from 1 (quite dissatisfied) to 4 (very satisfied).

Secondary outcomes (weight and pain)

Weight

Body weight was measured to the nearest 0.1 kg using a digital scale (Healthometer) and height to the nearest centimeter using a wall stadiometer, which were used to calculate BMI.

Patient-reported outcomes measurement information system pain measures

On the 3-item Patient-Reported Outcomes Measurement Information System (PROMIS) pain intensity measure [52], participants rated their average and worst pain during the past 7 days, as well as pain at the time of questionnaire completion by providing a 1 (no pain) to 5 (very severe) pain rating. This scale demonstrates adequate reliability and validity in chronic pain populations [53]. The PROMIS Pain Interference scale [54] includes eight questions examining pain-related impairment in social, cognitive, emotional, physical, and recreational activities over the past 7 days. Ratings were made from 1 (not at all) to 5 (very much). The PROMIS Physical Function measure includes four questions to examine the difficulty with which an individual could complete certain functional tasks. Ratings are made from 5 (without any difficulty) to 1 (unable to do). The Pain Interference and Physical Function scales demonstrate good reliability and validity [55, 56].

Pain impact

Based on Research Task Force criteria by Deyo and colleagues [57], pain impact was assessed by a combination of 9-items from the PROMIS–Short Form [54, 57] assessing pain intensity (“in the past 7 days, how would you rate your pain on average), pain interference (e.g., “how much did pain interfere with your day-to-day activities”), and functional status (e.g., “are you able to do chores such as vacuuming or yard work”). Items were summed, with impact stratification scores calculated based on the following categories: score 8 to 27 (mild pain impact), score 28 to 34 (moderate pain impact), score ≥ 35 (severe pain impact).

Short physical performance battery

The Short Physical Performance Battery (SPPB) assesses functional capacity based on the performance on three tests of lower-extremity function: standing balance, 4-min walking speed, and the ability to rise from a chair. Participants receive a score based on their performance for each test ranging from 0 (worst performance) to 4 (best performance), with total scores ranging from 0 to 12. The SPPB is a psychometrically valid and reliable instrument to assess physical performance among older adults [58].

Process measures

Physical activity

The Community Health Activities Model Program for Seniors (CHAMPS) [59] assesses weekly frequency and duration of a variety of lifestyle physical activities (e.g., gardening) and planned physical activity (e.g., walking, yoga) for seniors over the prior 4 weeks. Total frequency (events/week) and duration (hours per week) were calculated for all physical activity, and separately for moderate-to-vigorous physical activity. The CHAMPS demonstrates adequate test–retest reliability in older adult populations [60, 61].

Meaningful activity participation

Participants completed the Meaningful Activity Participation Assessment (MAPA) [62], a 28-item checklist reflecting common activities that are meaningful to older adults. Items are rated both for how commonly the activity is completed from 0 (not at all) to 6 (every day) and how meaningful the activities are perceived to be from 0 (not at all meaningful) to 4 (extremely meaningful). The frequency and meaningfulness of each activity are multiplied, then the values from each activity are added to create a total score meant to reflect the extent of engagement in meaningful activities. Total MAPA scores can range from 0 to 672. In a general population, the MAPA has good psychometric properties [62].

Positive and negative affect schedule

The Positive and Negative Affect Schedule (PANAS) is a 20-item scale consisting of 10 positively-valenced and 10 negatively-valenced terms, each rated on a 5-point scale ranging from 1 (very slightly or not at all) to 5 (extremely) resulting in scale scores for Positive Affect (PA) and Negative Affect (NA). The PANAS has high internal consistency and strong convergent and discriminant validity [63].

Food pain coping questionnaire

To assess the extent to which participants used food to cope with pain, we developed the 2-item Food Pain Coping Questionnaire (FPCQ). Participants are asked to report what they “generally do and feel when you experience chronic pain flare-ups” with prompts for “I eat more of my favorite foods to make myself feel better” and “I eat more than I usually do.” Response options for each item range from 1 (not at all) to 4 (a lot) and the sum of the two items was computed. Internal consistency for the FPC was good (α_T1 = 0.88, α_T2 = 0.88, α_T3 = 0.87).

Participant interviews

At the end of the study, all participants were invited to complete an interview to share their experiences with the intervention. Interviews were conducted by the Research Coordinator and included questions about the most helpful aspects of the intervention, their thoughts on specific components aimed at increasing environmental reward, their perceptions of the intervention materials and individual phone calls, and any additional feedback they wished to share. Notes were taken during interviews and interpreted by the research team.

Sample size justification

The target sample size (n = 40) was selected based on feasibility considerations and recommendations in the literature for pilot studies focused on estimating feasibility outcomes such as recruitment and retention rates [64]. Assuming a recruitment rate of approximately 2.5 participants per week during active enrollment (i.e., 10 participants per month), a sample size of 40 would allow estimation of the recruitment rate with a two-sided 95% CI of approximately 7 to 13 participants per month. Similarly, assuming a retention rate of approximately 80%, this sample size would allow estimation of retention with a 95% CI of approximately 68% to 92%.

Statistical analysis

PROMIS measures were transformed into T-scores, with norms based on a United States general population mean of 50 (standard deviation of 10). Feasibility outcomes, such as recruitment and retention results, were reported with descriptive statistics for continuous measures using means and standard deviations, and categorical measures were presented with counts and percentages. Pre- to 4-month and pre- to 8-month changes in outcomes were reported as mean differences with 95% confidence intervals (95% CI). Participants who withdrew from the study were excluded in the data analyses. For example, to examine changes from pre- to 4-month assessment, only participants who were present at both pre-test and the 4-month follow-up were included. Analyses were performed using SAS 9.4.

Results

Participant characteristics

Characteristics of participants are shown in Table 4. Most participants were female (76%), and the average age of the sample was 60.9 years (SD = 6.9). Intervention groups were created with a mean of 4.7 participants per group.

Table 4.

Baseline characteristics of study participants

	Total sample (n = 33)
	M or n	SD or %
Age (years)	60.9	6.9
Baseline weight (kg)	111.7	23.2
Baseline BMI (kg/m2)	39.8	7.0
Gendera
Women	24	72.7
Men	9	27.3
Race
Black	12	36.4
White	19	57.5
Biracial	2	6.1
Ethnicitya
Hispanic/Latino	0	0.0
Non-Hispanic	31	93.9
Marital
Married/Partnered	16	48.5
Not married/Partnered	19	51.5
Educationa
High school/GED	3	9.1
Some college	10	30.3
Two-year degree	5	15.2
Four-year degree	4	12.1
Graduate/Professional degree	7	21.2
Employment
Employed full-time	6	18.2
Employed part-time	5	15.2
Retired	9	27.3
Disabled	13	39.4
Income
< $20,000	8	24.3
$20,000–39,999	14	42.4
$40,000–59,999	3	9.1
$60,000–99,999	6	18.2
> $99,999	2	6.0

^aSome data not reported by participants

Intervention feasibility: recruitment and retention

Figure 2 shows the flow of participants through the study and Table 3 shows results for pre-specified benchmarks for success for feasibility outcomes. Screening by phone was completed by 132 patients of whom 70 were eligible. Not meeting pain impact threshold was the most common reason for ineligibility (n = 23). Forty-two individuals attended a baseline screening/enrollment session, and 33 of these were eligible and enrolled in the trial (i.e., attended intervention session 1). Approximately 79% of participants (n = 26) who commenced treatment were retained at the 4-month assessment, and 58% (n = 19) were retained at the 8-month assessment.

Fig. 2.

Flowchart of participant recruitment

During the first 4 months of the intervention (core sessions), eight individuals (24.2%) terminated treatment (defined as not attending the final group session). Reasons for termination include lost to follow-up, n = 3; lack of/loss of interest, n = 3; scheduling conflicts, n = 2. Notably, all withdrawals were in the first four intervention groups, whereas in the final three groups, all participants were retained through the entire intervention. Among the 25 participants who completed the core group sessions, six participants chose not to continue to the elective sessions. Among these 19 participants who initiated the elective phase, two dropped out prior to the end of the intervention. For core modules, completers attended an average of 7.7 sessions (SD = 0.74) corresponding to a 96% completion rate, compared to 2.1 sessions (SD = 1.46) among participants who withdrew. For optional modules, completers attended an average of 7.5 group sessions (SD = 1.42), reflecting a 94% completion rate. Of the eight individual phone sessions offered during the core modules, participants attended an average of 7.5 (SD = 0.95) sessions, also representing a 94% completion rate. Across all enrollees (completers and non-completers), approximately 79.9% of core sessions were attended overall (81.4% for core group sessions and 78.4% for core individual sessions).

Intervention acceptability: intervention engagement and satisfaction

At baseline, participants rated treatment credibility with a mean score of 7.8 out of 10.0 (SD = 1.3, range: 5.3–10.0). Participant reported engagement levels were high for both core sessions (mean = 6.4 out of 8.0, SD = 1.5, range: 1.2–8.0) and optional sessions (mean = 6.9 out of 8.0, SD = 1.2, range: 4.5–8.0). Treatment satisfaction ratings were high at 4 months (mean = 3.5 out of 4.0, SD = 0.66, range: 2.0–4.0) and 8 months (mean = 3.7 out of 4.0, SD = 0.45, range: 3.0–4.0).

Secondary outcomes (weight and pain)

Table 5 reports pre- to post-intervention changes at the 4-month and 8-month timepoints for secondary outcomes. Mean weight loss was 2.9 kg (SD = 4.2, 95% CI: − 4.61, − 1.16) at 4 months, representing 2.4% (SD = 3.8) of participants’ baseline body weight. At 8 months, the mean weight loss was 3.6 kg (SD = 6.0, 95% CI: − 6.54, − 0.61), or 3.0% (SD = 5.6) of baseline body weight. A weight loss threshold of ≥ 5% was achieved by 4 participants (15.4%) at 4 months and by 4 participants (22.2%) at 8 months. At 4 months, 22 participants (88% with available data) lost weight, while three participants (13%) gained weight. At 8 months, 13 participants (72.2%) lost weight and 5 (27.8%) gained weight.

Table 5.

Outcome and process measures

	Baseline n = 26		4-Mo assessment n = 26		Change 4Mo-baseline		Baseline n = 19		8-Mo assessment n = 19		Change 8Mo-Baseline
Measure	Mean	SD	Mean	SD	Mean Dif	95% CI	Mean	SD	Mean	SD	Mean Dif	95% CI
Weight and pain outcomes
Weight, kg	114.0	23.1	111.1	22.3	− 2.9	− 4.6, − 1.2	109.4	20.4	105.8	19.2	− 3.6	− 6.5, − 0.6
Pain Impact	32.7	5.7	28.7	7.6	− 4.0	− 6.8, − 1.3	32.6	5.2	26.0	7.4	− 6.6	− 9.4, − 3.8
PR-Pain Intensity	65.1	5.5	62.6	7.6	− 2.5	− 5.5, 0.6	65.8	5.4	61.3	5.9	− 4.5	− 6.8, − 2.2
PR-Pain Interference	65.3	4.8	61.3	6.8	− 4.0	− 6.6, − 1.3	65.0	4.0	58.6	6.3	− 6.4	− 8.9, − 3.9
PR-Physical Functioning	33.1	4.8	34.2	5.9	1.1	− 0.4, 2.7	33.5	4.6	37.4	5.7	4.0	1.9, 6.0
SPPB − Function	7.9	2.5	8.4	2.8	0.5	− 0.2, 1.2	8.3	2.7	8.9	2.7	0.6	0.02, 1.2
Process variables
CHAMPS Frequency Any	9.7	8.4	15.4	9.9	5.7	1.2, 10.1	11.4	9.0	16.3	11.9	4.9	− 1.5, 11.3
CHAMPS Frequency MV	3.1	4.2	5.7	6.5	2.6	0.2, 5.1	3.4	4.6	6.7	6.0	3.3	0.5, 6.0
CHAMPS Duration Any	7.4	5.1	11.1	5.6	3.7	1.3, 6.0	7.8	5.3	11.4	6.4	3.6	0.6, 6.6
CHAMPS Duration MV	3.0	4.0	4.0	4.1	1.0	− 0.8, 2.9	3.0	4.1	5.5	3.8	2.5	0.9, 4.1
MAPA Engagement	380.8	90.7	387.2	105.6	6.4	− 28.2, 40.9	386.6	82.6	406.8	83.7	20.2	− 15.5, 55.9
PANAS-Positive Affect	31.5	8.0	33.3	7.3	1.7	− 1.1, 4.5	31.7	6.7	34.8	5.1	3.1	0.1, 6.2
FPQ-Food Coping	5.0	2.1	3.9	1.8	− 1.0	− 1.8, − 0.3	4.7	2.1	4.1	1.5	− 0.7	− 1.4, 0.2

Change calculated as [4-month – baseline], [8-month – baseline], with negative and positive values indicating decreases and increases, respectively, at follow-up assessment compared to baseline; SD standard deviation, Mean Diff mean difference, 95% CI 95% confidence intervals, PR patient-reported outcomes measurement information system, SPPB short physical performance battery, CHAMPS community health activities model program for seniors, MV Moderate-to-vigorous physical activity, MAPA meaningful activity participation assessment, PANAS positive and negative affect schedule, FPCQ Food Pain Coping Questionnaire

Pain impact demonstrated improvements (i.e., decreased impact) from pre- to post-intervention at 4 months (mean = − 4.0, SD = 6.8, 95% CI: − 6.77, − 1.31) and at 8 months (mean = − 6.6, SD = 5.9, 95% CI: − 9.40, − 3.75). A reduction in pain impact was observed in 23 participants (88.5%) and an increase in 3 (11.5%) at 4 months. At the 8-month timepoint, all 19 participants (100%) demonstrated a decrease in pain impact. While pain intensity and physical function did not change at the 4-month timepoints, pain interference decreased from baseline to 4 months (mean = − 4.0, SD = 6.5, 95% CI: − 6.59, − 1.33). Similarly, there were improvements in pain intensity (mean = − 4.5, SD = 4.8, 95% CI: − 6.79, − 2.19), pain interference (mean = − 6.4, SD = 5.2, 95% CI: − 8.90, − 3.91), and physical function (mean = 4.0, SD = 4.3, 95% CI: 1.87, 6.03) from pre-intervention to the 8-month timepoint. While there were no changes in SPPB functional performance at 4 months, improvements were noted at the 8-month assessment compared to pre-intervention levels (mean = 0.61, SD = 1.19, 95% CI: 0.02, 1.20).

As an exploratory analysis, associations between changes in weight and pain impact were examined. The correlation between change in weight and change in pain impact from baseline to 4 months was modest and non-significant (r = 0.25, p = 0.22), as was the correlation from baseline to 8 months (r = 0.27, p = 0.28).

Process variables

Table 5 presents the pre- to post-intervention changes at the 4-month and 8-month timepoints for process variables. At 4 months, physical activity levels as assessed from the CHAMPS increased in frequency by 5.65 per week (SD = 10.95, 95% CI: 1.23, 10.08) for any activity and 2.62 per week (SD = 6.11, 95% CI: 0.15, 5.08) for moderate-to-vigorous activity. Duration of activity also increased by 3.65 h (SD = 5.83, 95% CI: 1.30, 6.01) for any activity, although duration for moderate-to-vigorous activity did not change. At 8 months, change in frequency of any activity did not change, while frequency of moderate-to-vigorous activity increased (mean = 3.26, SD = 5.67, 95% CI: 0.53, 5.99). In terms of duration of activity, participants spent more hours for both any activity (mean = 3.58, SD = 6.22, 95% CI: 0.58, 6.58) and moderate-to-vigorous activity (mean = 2.47, SD = 3.34, 95% CI: 0.86, 4.08). Improvements in meaningful activity engagement were not detected at 4 or 8 months. Positive affect did not change at 4 months but increased from pre-intervention to the 8-month timepoint (mean = 3.11, SD = 6.33, CI: 0.05, 6.16). The food pain coping questionnaire revealed decreases in using food to cope with pain from pre-intervention to the 4-month timepoint (mean = − 1.04, SD = 1.82, CI: − 1.77, − 0.30), but these effects diminished at 8 months.

Qualitative feedback

Feedback from post-intervention interviews was largely positive, with participants highlighting the adoption of healthier habits, increased engagement in pleasurable activities, and improved coping with pain and stress. Many valued the individualized focus on goal setting and found the group setting particularly empowering as it offered accountability and support for meaningful change. However, participants also noted difficulty adhering to certain activities and goals (i.e., food tracking, maintaining a consistent physical activity routine while in pain), found aspects of the intervention repetitive, and experienced challenges with technology (i.e., Zoom). Additionally, while virtual sessions were reported to be less burdensome due to travel constraints, participants noted a preference for in-person sessions to provide a stronger sense of connection with others in the group.

Discussion

Obesity and chronic pain are highly comorbid, with evidence suggesting bidirectional relationships between the two conditions. While existing behavioral treatments are effective for pain and weight management, most interventions address pain and obesity independently, thereby overlooking the interplay between the two conditions. To address this gap, the current study evaluated the feasibility and acceptability of an integrated behavioral intervention that simultaneously delivered skills for pain management and weight loss and sought to promote engagement in meaningful and rewarding activities, hypothesized to play a critical role in the maintenance of both chronic pain and obesity.

Our findings indicate that the intervention was feasible to deliver and was well accepted, as evidenced by high levels of treatment satisfaction and session engagement. However, recruitment rates did not meet our pre-specified benchmark, suggesting the need for improved methods and sources of recruitment in a future trial. Intervention retention rates were also lower than anticipated, with 24% of participants discontinuing the intervention before the 4-month assessment timepoint, and an additional 24% not continuing with the elective phase. Notably, rates of drop-out decreased over the course of the trial (i.e., 100% retention of participants during the last two cohorts), which may reflect refinements in study procedures (e.g., enhanced protocol for contacting patients missing an assessment) or challenges related to implementing the intervention during the COVID-19 pandemic, particularly in the earlier phases of delivery. Feedback from post-intervention interviews was largely positive, with participants appreciating goal setting for increasing activity engagement and the group format for support. Suggestions for improvement included reducing repetition and exploring options for in-person connections.

Although the study was not designed or powered to evaluate efficacy, participants reported improvements in pain and increases in physical activity, alongside modest reductions in body weight. Importantly, clinically meaningful changes were observed in pain and physical functioning, particularly at the 8-month mark, reflected by an average 30% reduction in pain-related outcomes [65–67]. Two additional pilot trials and a large RCT combining pain and weight interventions have similarly reported reductions in pain outcomes and weight loss [26–28]. The current study differed from these prior studies in several respects, including its remote delivery format, targeted pain and disease population, and its emphasis on enhancing environmental reward. A fully powered trial comparing this integrated intervention with non-integrated approaches to addressing weight and pain would provide additional insights into the relative value of this model.

Participants also experienced a 2.4% reduction in baseline body weight at 4 months and a 3.0% reduction at 8 months. Though these results are modest when compared to typical behavioral weight loss interventions [68], this finding is not surprising as individuals with chronic pain face unique challenges to weight loss. Pain often acts as a significant barrier to physical activity and lifestyle changes, placing this population at greater risk for weight gain. In fact, evidence demonstrates that individuals with comorbid pain and obesity achieve worse weight loss outcomes during behavioral weight loss treatment [69]. Supporting this, a behavioral weight loss trial found that participants with chronic pain and obesity lost 33% less weight over 24 months, relative to those without chronic pain [70].

While pathways linking obesity and pain are complex and multifactorial, it was hypothesized that reductions in pleasant activity engagement and positive affect might serve as mechanisms contributing to pain and excess weight; however, our measure of meaningful activity engagement showed only modest increases over time. While speculative, the MAPA may not have accurately captured the specific activities targeted by the intervention or aligned with the weekly goals established by participants during individual sessions. It is also plausible that the intervention may not have been robust enough to achieve the desired magnitude of increase in activity engagement. In contrast, there was a notable increase in physical activity, as assessed by the CHAMPS, which may partially reflect success in fostering activity engagement. Furthermore, improvements in positive affect and pain outcomes were observed throughout the study, suggesting that the intervention may have influenced intermediary variables, potentially contributing to the observed changes. Future studies would benefit from additional content or time spent targeting meaningful activity engagement in addition to replicating these findings to confirm the observed changes in process variables.

Strengths and limitations

Our findings should be interpreted in light of several limitations. First, participants were recruited from one geographical region and women comprised the majority of participants, potentially limiting generalizability. As a pilot study, we intentionally did not include a control group and had a small sample size; this limits our ability to determine intervention impact, highlighting the importance of conducting a larger-scale randomized-controlled trial to more definitively assess efficacy. Finally, lifestyle behaviors and study outcomes (e.g., physical activity, pain) were self‐reported using validated surveys but are subject to recall and self‐presentation biases.

This study had several strengths including individualizing meaningful activity goals for a more tailored experience and the integration of a broad range of pain and weight management skills. We recruited a diverse sample (36% Black; 66% with less than a bachelor’s degree), thereby increasing generalizability to underrepresented populations. Importantly, this study is among the few to integrate pain coping skills training with lifestyle behavioral weight management for chronic pain and obesity [28], addressing a significant gap in treatments for individuals with these comorbidities.

Conclusions

This trial highlights the potential of a behavioral intervention simultaneously targeting both chronic pain and weight management, offering a foundation to address these common comorbidities. Areas for improvement were identified and underscore the potential for refining the intervention to enhance its feasibility and effectiveness in a larger randomized controlled trial. Tailoring strategies to mitigate pain-related challenges while fostering sustainable lifestyle changes is an important step in improving therapeutic options for patients with comorbid chronic pain and obesity.

Abbreviations

BMI

Body mass index

EMPOWER

Empowering the Management of Pain-Obesity-Weight through Enhanced Reward

UF

University of Florida

CBT

Cognitive behavioral therapy

ACT

Acceptance and commitment therapy

DPP

Diabetes Prevention Program

SPPB

Short Physical Performance Battery

CHAMPS

Community Health Activities Model Program for Seniors

MAPA

Meaningful Activity Participation Assessment

PANAS

Positive and Negative Affect Schedule

FPCQ

Food Pain Coping Questionnaire

Authors’ contributions

MM and EB contributed to the study conceptualization, interpretation of data, writing, and approval of the final version. JC contributed to the analysis and interpretation of data, writing, and approval of the final version. All other authors (KS, SM, SA) contributed to the interpretation of data, writing, and approval of the final version.

Funding

Research reported in this publication was supported by the National Institute on Aging (R21AG070642) awarded to MM and EB.

Data availability

All data relevant to the study are included in the article or uploaded as online supplemental information. Data from the current study are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

This study was conducted in accordance with the ethical guidelines of the Helsinki Declaration and was approved by the University of Florida Institutional Review Board (IRB202002133). All participants provided written informed consent prior to study procedures.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.