Conditions: Parkinson's Disease
Keywords: Parkinson's Disease Small Bowel Bacterial Overgrowth Weight Loss Gastrointestinal Rifaximin
Allocation: NON_RANDOMIZED | Intervention model: SINGLE_GROUP
Enrollment: 49
Healthy volunteers: no

Brief summary:
The potential role of small bowel bacterial overgrowth (SBBO) in weight loss occurring in patients with Parkinson's Disease (PD) has not previously been examined. Our hypothesis was that SBBO is an important contributor to the development of weight loss in individuals with PD. The investigators proposed to 1) examine the role of SBBO in weight loss occurring in patients with PD and 2) determine the response to its treatment with a poorly absorbed antibiotic. The investigators performed a prospective, observational case-control study (Part 1) with an open-label therapeutic component (Part 2). Cases were defined as those PD patients who experienced significant weight loss while Controls were defined as those PD patients who did not experience significant weight loss.

Detailed description:
Part 1:

Consecutive patients seen in the Parkinson's disease clinic at Mayo Clinic in Arizona were approached to participate. After the determination of their eligibility and appropriate signed informed consent, all PD patients (i.e., both Case and Control groups) underwent the following:

1. Assessment of demographic features, weight history and PD history
2. PD and other medications
3. Determination of PD severity using the Unified Parkinson's Disease rating scale
4. Gastrointestinal Symptom Severity Index (GISSI) and modified GISSI.
5. Determination of usual calorie and nutrient intake (Brief Block Food Frequency Questionnaire)
6. Paffenbarger physical activity questionnaire
7. Quality of life (SF12 and PD-specific)
8. Hospital Anxiety and Depression Scale
9. Glucose hydrogen breath test (SBBO test)
10. Qualitative assessments of smell and taste

All questionnaires were completed during the 2 hour breath test.

Part 2:

All individuals in the weight loss group (i.e., only the Case group) were offered open-label treatment with the poorly absorbed antibiotic, rifaximin, 550 mg PO twice a day for 14 days. Treatment did not depend upon the results of the bacterial overgrowth breath test. Thus, both normal and abnormal breath test subjects could have received antibiotic treatment. The patient was contacted by phone 1 month after treatment at which time the presence of GI symptoms was determined and inquiry made about any adverse effects related to rifaximin use. GI symptoms, quality of life, weight measurement, and breath testing were repeated at a 3 month study visit.

Arms:
arm 1: All individuals in the Case group (i.e., only the subjects who had lost weight) were offered open-label treatment with the poorly absorbed antibiotic, rifaximin, 550 mg PO twice a day (BID) for 14 days. Subjects in the case group were in the study for 3 months. arm 2: This arm consisted of subjects with Parkinson's Disease who had not experienced significant weight loss. These patients were in the study for one day.

Interventions: intervention 1: Rifaximin
Intervention descriptions: intervention 1: All individuals in the weight loss group (i.e., only the Case group) were offered open-label treatment with the poorly absorbed antibiotic, rifaximin, 550 mg PO BID for 14 days. Treatment will not depend upon the results of the bacterial overgrowth breath test. Thus, both normal and abnormal breath test subjects received antibiotic treatment.

Protocol document: