An interventional study of Probiotic Capsule and placebo capsule in COPD, COPD (Chronic Obstructive Pulmonary Disease) and Probiotic, sponsored by University Hospital of Split. Enrolling by invitation at 5 sites in Croatia. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-04-21.
Sponsored by University Hospital of Split · Not applicable, Interventional, and Treatment
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.
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.
5,520 studies on the registry are indexed under Pulmonary Disease, Chronic Obstructive; 856 are open to participants now.
This study's planned enrollment of 60 is close to the median of 62 across 3,839 interventional studies indexed under Pulmonary Disease, Chronic Obstructive.
Browse Pulmonary Disease, Chronic Obstructive studies →University Hospital of Split is the lead sponsor of 31 studies on the registry; 9 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Child-Pugh class
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
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
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.
Also known as: Lactobacillus plantarum, Lac.plantarum HEAL9, Lac.plantarum LP 6596, Saccharomyces boulardii, dietary supplement, probiotic supplement
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.
Also known as: placebo, placebo control
mMRC scale of dyspnea
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.
Time frame: 8 weeks
CAT questionnaire
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.
Time frame: 8, 16 weeks
Bristol stool scale
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.
Time frame: 8, 16 weeks
mMRC
To evaluate changes in dyspnea severity on the mMRC scale after 4, 12, and 16 weeks of probiotic administration.
Time frame: 4,12,16 weeks
IL-6
Changes in laboratory-measured IL-6 (interleukin-6) levels at baseline and after 8 weeks of probiotic administration.
Time frame: 8 weeks
Complete blood count
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.
Time frame: 8 and 16 weeks
Fibrinogen
To evaluate changes in serum concentration of fibrinogen (g/L) from baseline and after 8 and 16 weeks of probiotic administration.
Time frame: 8 and 16 weeks
CRP
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.
Time frame: 8 and 16 weeks
Metabolic blood parameters-glucose
To assess changes in concentration of plasma glucose (mmol/L) measured at baseline and after 8 and 16 weeks of probiotic administration.
Time frame: 8, 16 weeks
Metabolic blood parameters-urea
To assess changes in urea concentration (mmol/L) measured at baseline, 8 weeks, and 16 weeks of probiotic administration.
Time frame: 8, 16 weeks
Metabolic blood parameters-creatinine
To assess changes in creatinine concentration (µmol/L) measured at baseline, 8 weeks, and 16 weeks.
Time frame: 8, 16 weeks
Metabolic blood parameters-liver enzymes
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.
Time frame: 8, 16 weeks
Metabolic blood parameters-electrolytes
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.
Time frame: 8, 16 weeks
Metabolic blood parameters-lipid profile
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.
Time frame: 8, 16 weeks
Lung function
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 .
Time frame: 16 weeks
Acute exacerbations
To investigate the effect of probiotic strains on the incidence of acute exacerbations after 16 weeks.
Time frame: 16 weeks
Correlation IL-6 and CRP
To determine the correlation between IL-6 concentration and CRP after 8 weeks of probiotic administration.
Time frame: 8 weeks
Other correlations
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.
Time frame: 16 weeks
BMI
To evaluate the effect of probiotic strain administration on changes in body mass index (BMI) after 16 weeks of probiotic administration.
Time frame: 16 weeks
Plan to share: No — 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.
Started Mar 2026 (actual). Primary completion is estimated for Sep 2027, 18 months after the start.
Of 1,094 non-industry interventional studies with no phase under Pulmonary Disease, Chronic Obstructive, half reached primary completion within 22 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 41. This study's planned 18 months is below that.
Counting every sponsor, half of 1,181 studies reached it within 22 months; a quarter within 10 and three quarters within 39.
How these figures are worked out, and which studies are left out of them.
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Studies of the drug tested here: Probiotic
Pulmonary Disease, Chronic Obstructive →
University Hospital of Split