RecruitingNot Applicable

Preoperative Fasting and the Gut Microbiome Before Hip Replacement

Germany130 participantsStarted 2025-07-01

Plain-language summary

Postoperative complications occur in 5-15% of patients undergoing elective primary total hip arthroplasty (THA), including periprosthetic joint infection (PJI), thrombosis, wound healing disorders, and metabolic dysregulation. The gut microbiome and the systemic immune profile have both been implicated as modifiable contributors to perioperative complication risk. Preoperative therapeutic fasting has been shown to remodel the gut microbiome, lower proinflammatory cytokines, and improve metabolic parameters. This single-center, prospective, randomized, two-arm controlled trial at Charité - Universitätsmedizin Berlin investigates whether a structured 20-day preoperative fasting intervention (alternating cycles of the Buchinger Fastenbox and intermittent fasting) modulates two co-primary endpoints - plasma IL-8 (a central proinflammatory marker) and gut microbial alpha-diversity (Shannon index) - compared with standard preoperative care. Secondary endpoints include further immune markers (TNFα, IL-10, T-/B-/NK-cell subsets, activation/exhaustion markers, monocyte HLA-DR), microbiome composition and function, continuous glucose-monitoring and daily metabolic measures, patient-reported outcomes (HOOS, PROMIS-33, infection self-report), and clinical outcomes (postoperative complications per EBJIS criteria, length of stay). Adults aged 18-75 undergoing elective primary THA are stratified by metabolic status (metabolically healthy vs. metabolically unhealthy according to harmonized metabolic-syndrome criteria) and randomized 1:1 to the fasting intervention versus standard care. Stool and whole-blood samples are collected at baseline (Day -21), and at Day +7 post-operatively for shotgun-metagenomic sequencing and multiparameter flow cytometry, with additional cytokine blood samples at Day -1 and 6 h / 24 h / 72 h post-operatively. Continuous glucose monitoring is performed in all participants from Day -21 until surgery. Planned enrollment is 130 participants.

Who can participate

Age range

18 Years – 75 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Adults aged 18-75 years (inclusive) * Scheduled for elective primary total hip arthroplasty (THA) * Able and willing to provide written informed consent * Able to follow the 20-day preoperative fasting protocol independently at home (if randomized to the fasting arm) or willing to be randomized to either arm Exclusion Criteria: * Resorption disorder due to bowel disease (e.g. inflammatory bowel disease, short-bowel syndrome, active celiac disease) * Antibiotic therapy within the last 2 months before baseline (T0) * Probiotic, prebiotic, or symbiotic supplementation within the last 2 months before baseline (T0) * Inability or unwillingness to provide informed consent * Severe comorbidity precluding fasting (e.g. ASA ≥ IV, advanced renal/hepatic impairment, eating disorder) * BMI \< 18.5 kg/m² (underweight) * Concurrent participation in another interventional drug or device trial * Pregnancy or breastfeeding

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1This trial is looking at how fasting before hip replacement surgery affects gut bacteria and inflammation — does my own gut health or diet history make me a better or worse candidate to discuss this study with you?
2Since this trial is in Phase NA, meaning it seems to be more of an observational or procedural study rather than a drug trial, can you help me understand what would actually be different about my care if I participated versus having a standard hip replacement?
3The study is measuring a specific inflammatory marker called IL-8 and gut bacteria diversity at seven days after surgery — would knowing those results from my own procedure actually influence any decisions about my recovery or follow-up care?
4Given that one of the outcomes being tracked is surgical wound infection, is there anything about my personal health history that might put me at higher risk, and would participating in this study change how that risk is managed?
5Could joining this trial affect the timing or details of my preoperative fasting instructions in a way that might have any impact on my surgery or anesthesia, and is standard care just as safe an option for me right now?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Change in plasma interleukin-8 (IL-8) concentration from baseline to Day +7 post-operatively

Timeframe: Baseline (Day -21, before start of intervention) and Day +7 post-operatively

Change in gut microbial alpha-diversity (Shannon index) from baseline to Day +7 post-operatively

Timeframe: Baseline (Day -21, before start of intervention) and Day +7 post-operatively

Trial details

NCT IDNCT07651462

SponsorCharite University, Berlin, Germany

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2026-09-01

Contact for this trial

Nele Wagener, Dr. med.

+49 30 450 615076 nele.wagener@charite.de

View on ClinicalTrials.gov More Hip Osteoarthritis trials

Plain-language summary

Who can participate

Age range

18 Years – 75 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

What they're measuring

Change in plasma interleukin-8 (IL-8) concentration from baseline to Day +7 post-operatively

Timeframe: Baseline (Day -21, before start of intervention) and Day +7 post-operatively

Change in gut microbial alpha-diversity (Shannon index) from baseline to Day +7 post-operatively

Timeframe: Baseline (Day -21, before start of intervention) and Day +7 post-operatively