Probiotics in COPD: Effects on Symptoms, Lung Function, and Inflammation

April 19, 2026 updated by: Andrea Anić Matić,MD, University Hospital of Split

"The Effect of Probiotics on the Degree of Dyspnea, Lung Function, and Inflammatory Mediators in Patients With Chronic Obstructive Pulmonary Disease (COPD)."

The goal of this randomized, placebo controlled, double-blind clinical trial is to find out whether a probiotic supplement can help adults with chronic obstructive pulmonary disease (COPD) breathe better and better control their symptoms. The study will try to answer does taking a probiotic supplement, compare with a placebo, reduce shortness of breath, does it improve daily COPD symptoms or change stool patterns by using validated questionnaires; does it affect lung function or inflammation. The results of this study may contribute to a better understanding of the disease, the application of new therapeutic options, and provide a foundation for future research.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Detailed Description

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory condition characterized by persistent symptoms such as shortness of breath, chronic cough, sputum production, and periods of acute worsening. It is also associated with ongoing systemic inflammation, which contributes to symptom severity, impaired lung function, and increased risk of exacerbations. Emerging evidence suggests that the gut-lung axis may play a significant role in this inflammatory process. Probiotics, which help restore a healthy microbial balance and support gut barrier integrity, have been proposed as a potential strategy to modulate inflammation and respiratory symptoms. Several studies have suggested that probiotics may reduce respiratory symptoms, improve lung function and lower systemic inflammation in people with COPD.

This randomized study is designed to evaluate whether a probiotic supplement (Saccharomyces boulardii, Lactobacillus plantarum LP 6596, and Lactobacillus plantarum HEAL9) can improve shortness of breath, overall symptom burden, lung function, and selected inflammatory markers in adults with stable COPD compared with placebo. Participants will be recruited from multiple clinical centers and will continue their usual COPD therapy throughout the study period. A total of 60 adult participants with a confirmed diagnosis of COPD, stable disease and baseline dyspnea of mMRC (modified Medical Research Council) ≥ 1 will be randomized to receive either a probiotic supplement or placebo for 16 weeks. They will take either the probiotic supplement or placebo 2 capsules once daily for 16 weeks and will be examined at three clinic visits for symptom questionnaires- mMRC scale of dyspnea, CAT (COPD Assessment Test) and Bristol Stool Scale, blood sampling, and spirometry testing. Between clinic visits, participants will have regular telephone checks every 4 weeks to assess symptoms, adherence to the study product and possible side effects.

This trial aims to provide a more comprehensive understanding of how probiotic supplementation may influence dyspnea, quality of life, inflammatory activity, and respiratory function in COPD.

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Croatia
      • Karlovac, Croatia
        • General Hospital Karlovac
      • Split, Croatia, 2100
        • University Hospital Split
      • Vinkovci, Croatia
        • General Hospital Vinkovci
      • Zagreb, Croatia
        • University Hospital Centre Sestre Milosrdnice
      • Šibenik, Croatia, 2200
        • General Hospital Sibenik

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Patients with a previously established diagnosis of COPD, regardless of the degree of airflow obstruction on pulmonary function testing.
  2. Age over 18 years, regardless of sex.
  3. Stable disease without exacerbations during the past two months (8 weeks).
  4. Stable disease without changes to maintenance therapy during the past two months (8 weeks).
  5. Patients with an mMRC score of 1 or higher.
  6. Signed informed consent.

Exclusion Criteria:

  1. patients diagnosed with serious comorbidities such as severe cardiovascular diseases (severe heart failure, acute coronary syndrome, or percutaneous coronary intervention within 6 months, uncontrolled tachy/bradyarrhythmias), patients with severe renal failure and a placed central venous catheter, patients with severe liver damage (Child-Pugh class C), patients with infectious hepatitis or HIV, active bloody diarrhea;
  2. patients undergoing active oncological and hematological treatment;
  3. patients who have had a stroke within the past 3 months;
  4. transplanted patients, including allograft recipients;
  5. patients on long-term systemic corticosteroid and immunosuppressive therapy (oral or intravenous form) as well as antifungal therapy,
  6. patients who have had a COPD exacerbation within the past two months and are not in a stable condition,
  7. patients diagnosed with asthma,
  8. patients with a history of lung surgery or serious respiratory diseases other than COPD (active tuberculosis, sarcoidosis, pulmonary fibrosis, severe bronchiectasis, pulmonary aspergillosis, etc.),
  9. patients who have recently participated in other clinical trials or have received experimental therapy,
  10. patients with a history of severe allergic reactions or hypersensitivity to the components of the probiotic preparation,
  11. patients with active alcoholism or drug addiction,
  12. patients with severe psychiatric diagnoses or those with significant physical or cognitive limitations that would interfere with following the study protocol,
  13. patients who have recently undergone surgery,
  14. pregnant or breastfeeding women,
  15. patients who have taken any probiotic preparations within one month before the start of the study,
  16. patients whose COPD treatment is changed during the course of the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Probiotic arm
Participants will receive two capsules once daily of a probiotic dietary supplement for 16 weeks. The product will be coded to ensure blinding.
Dietary supplement: Probiotic Capsule
The participants will take two probiotic capsules per day for 16 weeks, containing S. boulardii, Lactobacillus plantarum LP 6596, and Lactobacillus plantarum HEAL9. The product will be coded for blinding purposes.
Other Names:
  • Lactobacillus plantarum
  • dietary supplement
  • Lac.plantarum HEAL9
  • Lac.plantarum LP 6596
  • Saccharomyces boulardii
  • probiotic supplement
Placebo Comparator: Placebo arm
Participants will receive two capsules once daily of a placebo preparation for 16 weeks. The product will be coded to ensure blinding.
Dietary supplement: placebo capsule
Participants will receive two capsules per day for 16 weeks, a placebo preparation that is identical in composition and form to the probiotic but does not contain an active substance. The product will be coded for blinding purposes.
Other Names:
  • placebo
  • placebo control

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
mMRC scale of dyspnea
Time Frame: 8 weeks
The primary objective of this study is to assess the degree of change in dyspnea, measured using the validated mMRC (Modified Medical Research Council) questionnaire in patients with COPD eight weeks after administration of the probiotic dietary supplement.
8 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
CAT questionnaire
Time Frame: 8, 16 weeks
To evaluate the effect of probiotic therapy on symptom control and quality of life in COPD patients using the validated CAT (COPD Assessment Test) questionnaire after 4, 8, 12, and 16 weeks of probiotic administration.
8, 16 weeks
Bristol stool scale
Time Frame: 8, 16 weeks
To assess the effect of probiotic therapy on stool appearance using the Bristol Stool Scale at baseline and after 8 and 16 weeks of probiotic administration.
8, 16 weeks
mMRC
Time Frame: 4,12,16 weeks
To evaluate changes in dyspnea severity on the mMRC scale after 4, 12, and 16 weeks of probiotic administration.
4,12,16 weeks
IL-6
Time Frame: 8 weeks
Changes in laboratory-measured IL-6 (interleukin-6) levels at baseline and after 8 weeks of probiotic administration.
8 weeks
Lung function
Time Frame: 16 weeks
To evaluate the effect of probiotics on spirometry-derived values: FEV₁% (forced expiratory volume in one second) (L), FVC% (forced vital capacity) (L), and the FEV₁/FVC ratio after bronchodilator testing at baseline and after 16 weeks of probiotic administration .
16 weeks
Acute exacerbations
Time Frame: 16 weeks
To investigate the effect of probiotic strains on the incidence of acute exacerbations after 16 weeks.
16 weeks
Correlation IL-6 and CRP
Time Frame: 8 weeks
To determine the correlation between IL-6 concentration and CRP after 8 weeks of probiotic administration.
8 weeks
Other correlations
Time Frame: 16 weeks
To determine the correlation between CRP concentration and spirometry findings (FEV₁ and the FEV₁/FVC ratio); correlation between fibrinogen levels and spirometry findings (FEV₁ and the FEV₁/FVC ratio); correlation between leukocyte count and spirometry findings (FEV₁ and the FEV₁/FVC ratio) after 16 weeks of probiotic administration.
16 weeks
BMI
Time Frame: 16 weeks
To evaluate the effect of probiotic strain administration on changes in body mass index (BMI) after 16 weeks of probiotic administration.
16 weeks
Complete blood count
Time Frame: 8 and 16 weeks
To investigate the effect of probiotics on changes in concentration of total leukocyte count (×10⁹/L) with differential ((concentration of neutrophil count (×10⁹/L) , eosinophil count (×10⁹/L), monocyte (×10⁹/L) and lymphocyte count (×10⁹/L)) at baseline and after 8 and 16 weeks.
8 and 16 weeks
Fibrinogen
Time Frame: 8 and 16 weeks
To evaluate changes in serum concentration of fibrinogen (g/L) from baseline and after 8 and 16 weeks of probiotic administration.
8 and 16 weeks
CRP
Time Frame: 8 and 16 weeks
To evaluate changes in serum concentration of CRP (C-reactive protein) in mg/L from baseline and after 8 and 16 weeks of probiotic administration.
8 and 16 weeks
Metabolic blood parameters-glucose
Time Frame: 8, 16 weeks
To assess changes in concentration of plasma glucose (mmol/L) measured at baseline and after 8 and 16 weeks of probiotic administration.
8, 16 weeks
Metabolic blood parameters-urea
Time Frame: 8, 16 weeks
To assess changes in urea concentration (mmol/L) measured at baseline, 8 weeks, and 16 weeks of probiotic administration.
8, 16 weeks
Metabolic blood parameters-creatinine
Time Frame: 8, 16 weeks
To assess changes in creatinine concentration (µmol/L) measured at baseline, 8 weeks, and 16 weeks.
8, 16 weeks
Metabolic blood parameters-liver enzymes
Time Frame: 8, 16 weeks
To assess changes in activity of Aspartate Aminotransferase (AST) A (U/L), Alanine Aminotransferase (ALT) (U/L) and Gamma-Glutamyl Transferase (GGT) (U/L) at baseline and after 8 and 16 weeks of probiotic administration.
8, 16 weeks
Metabolic blood parameters-electrolytes
Time Frame: 8, 16 weeks
To assess changes in concentration of sodium (mmol/L), potassium (mmol/L), and chloride (mmol/L) at baseline, after 8 and 16 weeks of probiotic administration.
8, 16 weeks
Metabolic blood parameters-lipid profile
Time Frame: 8, 16 weeks
To assess changes in concentration of total cholesterol (mmol/L), High-Density Lipoprotein-HDL(mmol/L), Low-Density Lipoprotein-LDL(mmol/L), triglycerides (mmol/L) at baseline, 8 weeks, and 16 weeks of probiotic administration.
8, 16 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University Hospital of Split

Collaborators

Abela Pharmaceuticals, Inc.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 8, 2026

Primary Completion (Estimated)

September 1, 2027

Study Completion (Estimated)

December 1, 2030

Study Registration Dates

First Submitted

January 2, 2026

First Submitted That Met QC Criteria

January 2, 2026

First Posted (Actual)

January 14, 2026

Study Record Updates

Last Update Posted (Actual)

April 21, 2026

Last Update Submitted That Met QC Criteria

April 19, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • UHS-COPD-PROBIO-2025
  • 2181-147/01-06/LJ.Z.-25-02 (Registry Identifier: Ethics Committee of University Hospital Split)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared because the study involves sensitive health information, and data sharing is not covered by the informed consent form or approved by the ethics committee. Only aggregated, anonymized study results will be made publicly available.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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