Complex Regional Pain Syndrome (CRPS) and the Gut-bacteria

Study Overview
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Brief Summary
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The purpose of this study is to investigate, for the first time, whether gut bacteria composition and function of patients with CRPS differ from those of healthy adults. Samples of stool, urine and blood will be collected from patients with CRPS and from healthy adults. The type and function of bacteria of CRPS patients will be analyzed and compared to those of healthy adults to test if potential differences could explain the mechanism/s involved with the development of CRPS.

Official Title
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Comparison of Gut Microbial Composition and Function in CRPS Patients vs. Healthy Individuals

Conditions
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CRPS

Intervention / Treatment
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* Diagnostic Test: Stool and blood samples
* Other: Physical examination
* Other: Questionnaires


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Women and men over the age of 18, diagnosed with CRPS of the upper or lower limb according to the Clinical Budapest Criteria, with a duration of 6 months and over (for the 1st study group). Healthy women and men over the age of 18, who share a household with a CRPS patients participating in the study (for the 1st control group). Healthy women and men over the age of 18 (for the 2nd control group). Be able to read and write in either French, English or Hebrew. Exclusion criteria: Any major illness (eg. malignancy, active inflammatory disease, metabolic disease, etc.) Pregnancy Chronic pain conditions (other than CRPS in the patients group) Acute illness of any type in the preceding 1 month Use of systemic antibiotics in the preceding 1 month Change in any other regularly taken medications in the past 1 month Substantial dietary / gastrointestinal alterations in the past 1 month. The inclusion/exclusion criteria were set to reduce the risk of confounding factors that could affect gut microbiota composition.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| CRPS (Complex Regional Pain Syndrome)<br>Participants with CRPS (Complex Regional Pain Syndrome)) | Diagnostic Test: Stool and blood samples<br>* fecal microbiome and metabolomics, as well as metabolites in plasma<br>Other: Physical examination<br>* physical examination performed by a physician to confirm CRPS diagnosis and assess patient's eligibility to participate in the study. The exam will include skin temperature measured using a laser/infrared skin thermometry.<br>Other: Questionnaires<br>* Questionnaires measuring pain level, sleep, mood and diet parameters.<br>|
| Healthy<br>Healthy individuals | Diagnostic Test: Stool and blood samples<br>* fecal microbiome and metabolomics, as well as metabolites in plasma<br>Other: Questionnaires<br>* Questionnaires measuring pain level, sleep, mood and diet parameters.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gut microbiome composition | Assessment of genomic composition of the gut bacteria by differential abundance analysis will be performed using 16S rRNA (Genome-Quebec) | 1 day | 
| Presence of stool microbiota-related metabolites affecting host physiology | Concentration of bile acids and short-chain-fatty-acids through Metabolomics analysis (Metabolon, USA). | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Short-form health-questionnaire (SF12) score | A 12-item measure of health-related quality of life, validated in a variety of population groups | 1 day | 
| Brief Pain Inventory (BPI) score | A 12-item questionnaire evaluating function level and disability among pain patients | 1 day | 
| Patient Health Questionnaire (PHQ-9) score | A 9 item inventory rated on a 4 point Likert-type scale used for screening for depression and anxiety | 1 day | 
| Pittsburg Sleep Quality Index (PSQI) scores | A standardized self-administered questionnaire for the assessment of subjective sleep quality | 1 day |