Weight Loss in Parkinson's Disease and Role of Small Bowel Bacterial Overgrowth

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.