Efficacy of gut microbiota-targeted therapies in Parkinson’s disease: a systematic review and meta-analysis of randomized controlled trials
Bibliographic record
Abstract
Objective: This study aimed to investigate the efficacy of gut microbiota (GM)-targeted therapies in treating Parkinson's disease (PD). Methods: Randomized controlled trials (RCTs) were retrieved from PubMed, Embase, Cochrane, and WOS from database inception to June 2025. The eligible RCTs employed GM-targeted therapies, including antibiotics, probiotics, synbiotics, or fecal microbiota transplantation (FMT), as adjunct treatments for PD. Data were pooled using a random-effects model, and the effect sizes were expressed as standardized mean differences (SMDs). In addition, the quality of evidence for all outcomes was assessed using the GRADE framework. Results: This study demonstrated that GM-targeted therapies significantly improved PD outcomes, including Movement Disorder Society-Unified Parkinson Disease Rating Scale (MDS-UPDRS) III (SMD: -0.34, 95%CI: -0.57 to -0.11, P = 0.004), bowel movements (BMs) (SMD: 1.27, 95%CI: 0.35 to 2.2), use of laxatives (SMD: -0.33, 95% CI: -0.65 to -0.02), malondialdehyde (MDA) (SMD: -0.69, 95%CI: -1.23 to -0.15) indicators. However, there were no significant improvements in MDS-UPDRS I (SMD: -0.64, 95%CI: -1.42 to 0.13), MDS-UPDRS II (SMD: -0.28, 95%CI: -0.70 to 0.14), MDS-UPDRS IV (SMD: -0.08, 95% CI: -0.82 to 0.66), Mini-Mental State Examination (MMSE) (SMD: -0.01, 95% CI: -0.30 to 0.29), Montreal Cognitive Assessment (MoCA) (SMD: 0.04, 95%CI: -0.53 to 0.60), non-motor symptom scale (NMSS) (SMD: -0.11, 95%CI: -0.94 to 0.72), Parkinson's Disease Questionnaire-39 (PDQ-39) (SMD: -0.19, 95%CI: -0.58 to 0.20), total antioxidant capacity (TAC) (SMD: 0.29, 95%CI: -0.04 to 0.62), glutathione (GSH) (SMD: 0.51, 95%CI: -0.02 to 1.03), and Geriatric Depression Scale-15 (GDS-15) (SMD: -0.37, 95%CI: -0.87 to 0.12). Conclusion: GM-targeted therapies may improve motor symptom scores (as measured by MDS-UPDRS III), alleviate constipation, and reduce blood malondialdehyde levels in PD patients. However, they did not significantly impact the scores for cognitive function, PD neuropsychiatric, behavioral, and emotional symptoms, and activities of daily living in this analysis. Given the inherent limitations of the included studies (such as small sample sizes and heterogeneity), future large-scale and rigorously designed RCTs are needed to validate these preliminary findings. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42024606415.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.023 | 0.052 |
| Meta-epidemiology (narrow) | 0.004 | 0.002 |
| Meta-epidemiology (broad) | 0.030 | 0.042 |
| Bibliometrics | 0.009 | 0.009 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".