Diet Interventions: Remitted and Evaluated as Complementary Treatments for Pain

NCT05785884 | Recruiting

• 1 other identifier: IRB-300005524
• Study Type: interventional
• Target: 200
• Locations: 1 country
• Sites: 1

Brief Summary

Knee osteoarthritis (OA) is the most prevalent form of arthritis, a significant cause of disability in the U.S. With an aging population and the rise in obesity rates, the prevalence of knee OA is expected to climb, significantly reducing quality of life (QOL) for those suffering from this debilitating condition. Current national efforts to reduce analgesic utilization highlight the critical need for safe, effective, and accessible alternatives for pain relief. Low-carbohydrate diets (LCDs) reduce inflammation and pain independent of weight loss, indicating that diet interventions offer a non-pharmacological complementary treatment. However, differences exist in metabolism that are rarely addressed in diet intervention studies. Thus, it is important to assess the potential of different diets in a broad population of chronic pain sufferers to determine the potential of diets to reduce knee OA pain. We have shown that a LCD was associated with reduced evoked knee OA pain, daily pain and oxidative stress when compared to either a USDA diet or a diet-as-usual control. Both experimental diets reduced weight to a similar degree, arguing that diet quality was likely the key factor in pain reduction, as opposed to weight loss. However, previous studies comparing diets have utilized diet prescriptions with less control for adherence to the diets. To overcome this obstacle, and in line with our recent work, we will provide all snacks and meals during the diet intervention to increase adherence and retention in the study, allowing for better control over diet interventions and consistency of foods within each study group. We will recruit adults with knee OA (N=200) to complete our two-phase protocol. Phase 1 will involve a 1-week diet run-up that will allow for quantification of pain measures, psychosocial variables (socioeconomic status, nutritional knowledge, proximity to grocery stores, food insecurity), and diet quality to provide a baseline for comparison. Phase 2 will be a 6-week randomized diet intervention (LCD or USDA diet) in which both groups will be provided with all meals at the direction of study personnel and input from participants. Evoked pain tasks, measures of pain disability, severity, catastrophizing, and interference will be assessed every 3 weeks in addition to QOL measures, mood, and depression. Physiological variables will be assessed through blood draws (inflammatory profile) and dual-energy X-ray absorptiometry scans (DXA; body composition, visceral fat) at the end of Phases 1 and 2. This will be the first study to examine the efficacy of these diets to reduce knee OA pain with an emphasis on interactions with biopsychosocial variables. Changes in all pain measures following Phase 2 will be assessed with respect to published measures of clinically-meaningful differences in pain and disability, as well as for statistical significance. The central hypothesis is that the LCD will improve pain and QOL in participants with knee OA more than the USDA diet, but that both will be beneficial. Specific Aim 1: To investigate the efficacy of the diets to reduce pain and improve QOL. Hypothesis 1: The LCD group will show significantly greater reductions in: a) self-reported pain (\>1.7 in pain intensity) and, b) evoked pain (\>30%) when compared to the USDA diet. Hypothesis 2: The LCD group will show greater improvements in: a) QOL, b) mood, and c) self-reported improvement (\>50% participants reporting "much improved" or "very much improved"). Hypothesis 3 (secondary): Both diets will result in improved pain disability, severity, catastrophizing and pain related fear; the LCD will outperform the USDA diet. Specific Aim 2: To explore individual differences in diet and baseline measures. Hypothesis 1: Baseline diet quality will be negatively associated with baseline pain sensitivity Hypothesis 2: Those reporting greater a) food insecurity and/ or b) proximity to grocery stores will report poorer-quality diets. Specific Aim 3: To determine whether physiological variables contribute to diet effects or lack thereof. Hypothesis 1: Baseline physiological measures (inflammatory profile) will predict: a) pain sensitivity, and b) reductions in pain. Hypothesis 2: Change in physiological measures (inflammatory profile, adiposity, leptin) will be related to: a) change in pain measures, b) change in QOL, c) self-reported improvement and, d) mood.

Conditions

Knee Osteoarthritis

Keywords

diet; chronic pain; knee osteoarthritis; racial differences

Outcome Measures

Primary Outcomes (3)

• Western Ontario and McMaster Osteoarthritis Index pain change

  The Western Ontario and McMaster Osteoarthritis Index (WOMAC) pain score is a 0-20 score with higher scores reflecting more severe pain. Questions 1-5 are summed to provide a WOMAC pain score. Change scores will be calculated. Greater change scores would reflect more improvement.

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

• BPI pain change

  The Brief Pain Inventory (BPI) pain score is a 0-40 score with higher scores reflecting more pain. Questions 3-6 are scored on 0-10 and are summed to provide an overall pain score. Change scores will be calculated.

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

• TUG pain intensity change

  Before and after the Timed-Up-And-Go (TUG) task, participants will be asked to rate the intensity of pain in their knee on a 0-100 scale. The difference in the ratings will be considered the evoked pain score. Change scores will be calculated.

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

Secondary Outcomes (6)

• WOMAC physical function

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

• BPI pain interference change

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

• Temporal Summation pain intensity change

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

• Repeated Chair Stand pain intensity change

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

• SF-36 Quality of Life change

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

Other Outcomes (5)

• TUG time to completion change

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

• Repeated Chair Stand time to completion change

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

• Timed Walk pain intensity change

  Baseline (week 0), immediately before the intervention (week 3), 3 weeks after initiating the intervention (week 6), immediately after the intervention (week 9)

Study Arms (2)

Low Carbohydrate Diet

EXPERIMENTAL

Adults ages 40-75 with knee OA.

Behavioral: Diet

USDA Diet

EXPERIMENTAL

Adults ages 40-75 with knee OA.

Behavioral: Diet

Interventions

Diet BEHAVIORAL

A 6 week randomized diet

Low Carbohydrate Diet; USDA Diet

Eligibility Criteria

• Age: 40 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• diagnosis of knee OA
• pain in at least 4/7 days/week for the past 3 months (pain of ≥3/10 on 0-10 scale)
• age between 40-75
• average daily consumption of \>100 g carbohydrates (based on Phase 1 food checklist)
• understanding of verbal and written English
• self-identification as either NHB or NHW
• BMI between 25 and 40 kg/m2

You may not qualify if:

• unmedicated diabetes
• unwillingness to follow prescribed diets
• recent weight change (\>4 kg in past month)
• currently on a diet
• history of eating disorders or other psychiatric disorders requiring hospitalization within the past 6 months
• digestive diseases
• difficulty chewing or swallowing
• reliance on others for meal preparation
• cardiovascular or pulmonary disease
• daily opioid pain medications
• use of medications known to alter metabolism or digestion (e.g., proton-pump inhibitors)
• use of anti-hypertensive medications that affect glucose tolerance
• use of tobacco
• participation in extreme exercise
• knee replacement

Sponsors & Collaborators

• University of Alabama at Birmingham: lead

Study Sites (1)

University of Alabama at Birmingham

Birmingham, Alabama, 35294, United States

RECRUITING

MeSH Terms

Conditions

Osteoarthritis, Knee; Chronic Pain

Interventions

Diet

Condition Hierarchy (Ancestors)

Osteoarthritis; Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Officials

• Robert E Sorge, PhD

  University of Alabama at Birmingham

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Robert E Sorge, PhD

CONTACT

12059348563; rsorge@uab.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Model Details: All participants assigned to a single diet intervention. Between-groups differences and within-group changes will be assessed.

Study Record Dates

• First Submitted: March 14, 2023
• First Posted: March 27, 2023
• Study Start: February 1, 2023
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2027
• Last Updated: August 6, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: For 5 years following final data analysis
• Access Criteria: De-identified data can be made available on encrypted servers for researchers whose research plans do not overlap with the aims of the current project. Requests will be assessed by the PI and Co-Is as needed.

Locations

US (1)