[Does eradication of the organism Helicobacter pylori from the gut of patients with Parkinson's disease improve the absorption of the main drug used to treat patients symptoms?]

Helicobacter pylori (H pylori) is a common infection of the gut and is often associated with duodenal and gastric ulcers. The exact mechanism is unknown but there is some evidence that infection with H pylori can interfere with the absorption of some drugs in the gut. One such drug is levodopa, the main drug used to treat the motor symptoms of Parkinson's disease. Whilst levodopa is very effective for treating Parkinson's symptoms, after time it can become less effective in some patients which may be due to variable absorption. If H pylori is eradicated with the use of antibiotics then absorption of levodopa may be improved and in turn the patient's motor symptoms may be improved.

It is unknown how many people with Parkinson's disease are also infected by H pylori and this needs to be established. We searched the literature for all studies of H pylori and Parkinson's disease and found four studies which reported that between 37% and 59% of Parkinson's disease patients are H pylori-positive. This is similar to the rate in the general population.

We used clinical trials to see if treatment of H pylori-positive Parkinson's disease patients with antibiotics improved the absorption of levodopa and improved their motor symptoms. Only two completed trials were found from our searching. We did not pool these as they had different objectives and used different outcome measures. One of the trials reported a significant increase in levodopa absorption and improvement in motor symptoms when antibiotics were used to eradicate H pylori. The other completed trial did not have any usable results. A further trial of H pylori eradication in Parkinson's disease is still underway and the results, which are due in 2010, will help inform further studies.

Very little information was found about H pylori eradication in Parkinson's disease. More clinical trials are needed using standard measures of motor symptoms. It will be important also to look at the cost of both screening for H pylori and treatment of H pylori in Parkinson's disease patients to see if this is worthwhile.

Authors' conclusions: 

There is currently a lack of evidence on the effects of screening and treating H pylori in patients with Parkinson's disease. There is limited evidence to suggest that H Pylori eradication improves the absorption of levodopa and improves motor symptoms. Results from an ongoing trial will inform the evidence base and will be incorporated in an update of this review. There is a need for well-conducted randomised controlled trials with standard outcome measures for motor symptoms and incorporating the costs of screening and treatment.

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Background: 

Levodopa is the mainstay of treatment for alleviating the motor symptoms associated with Parkinson's disease. However, patients often experience fluctuations in their symptoms over time and 'wearing off' which may be partly related to variable absorption of the drug. There is some evidence that treatment of the common gastrointestinal infection Helicobacter pylori (H pylori) with antibiotics may improve levodopa absorption in the gut and hence improve symptoms.

Objectives: 

1)  What is the prevalence of H pylori in Parkinson’s disease patients?
2)  Does treatment of H pylori infection with antibiotics improve symptoms in Parkinson’s disease patients? Is this effect dependent on improvements in the absorption of levodopa?

Search strategy: 

We searched electronic databases (including CENTRAL, MEDLINE, EMBASE, PsycINFO and CINAHL) and trial registers, handsearched conference proceedings and carried out citation searching on key articles. All searching was updated in August 2009. We contacted authors to provide additional information where necessary.

Selection criteria: 

Clinical trials in patients with a well-defined definition of Parkinson's disease and who were H pylori-positive. Two people independently selected studies for inclusion using predetermined criteria. We used recruitment figures from clinical trials and other studies identified from the searching to determine the prevalence of H pylori in Parkinson's disease.

Data collection and analysis: 

Two authors abstracted data from the source papers and assessed methodological quality independently. We presented results descriptively.

Main results: 

Two completed and one ongoing clinical trial met the inclusion criteria. One trial (34 patients randomised) examined the effects of H pylori eradication on levodopa absorption and motor symptoms and found significant improvements in both. The ongoing trial has similar objectives and aims to recruit 100 patients. The other completed trial (20 patients analysed) sought to find a causal link between infection with H pylori and Parkinsonism and was non-contributory. A worsening of symptoms was noted with eradication failure.

The prevalence of H pylori in Parkinson's disease was reported in four studies and ranged from 37% to 59% which is similar to that of the general population.

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