Evidence map›Paper›PMID 33164946›Full record

ReviewJournal of Parkinson's disease2021

Effects of Helicobacter pylori on Levodopa Pharmacokinetics.

Dag Nyholm, Per M Hellström

Open access · hybridAbstract readReview
PubMed Full text at PMC Publisher
In one paragraph

Review in Journal of Parkinson's disease, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 24 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
24citing papers in PubMed, 1 pooled it
3.9field-weighted citation impact, top 6% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

24 citing papers in PubMed, 1 synthesis or guideline pooled it, 32 citations in OpenAlex.

  1. Pooled it
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  8. Management of Gastrointestinal Symptoms in Parkinson's Disease.Journal of central nervous system disease · 2025
    Review
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  11. Causal associations betweenFrontiers in immunology · 2024
    Article
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

2 authors at 1 institution in 1 country.

Dag NyholmDepartment of Neuroscience, Neurology; and Department of Medical Sciences, Gastroenterology, Uppsala University, Sweden.
Per M HellströmDepartment of Neuroscience, Neurology; and Department of Medical Sciences, Gastroenterology, Uppsala University, Sweden.
Uppsala University · SE

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundInfection with Helicobacter pylori seems overrepresented in Parkinson's disease. Clinical observations suggest a suboptimal treatment effect of levodopa in Helicobacter positive patients.

objectiveDescribe and explain the connection between a Helicobacter pylori infection of the upper gut and changes in pharmacokinetics of oral levodopa treatment in Parkinson's disease.

methodsPubMed, Google Scholar, and Cross Reference search was done using the key words and combined searches: Bioavailability, drug metabolism, dyskinesia, Helicobacter, L-dopa, levodopa, motor control, pharmacodynamics, pharmacokinetics, prevalence, unified Parkinson's disease rating scale.

resultsThe prevalence of Helicobacter pylori in Parkinson's disease patients is reported to be about 1.6-fold higher than in a control population in some studies. Helicobacter has therefore been assumed to be linked to Parkinson's disease, but the mechanism is unclear. As regards symptoms and treatment, patients with Parkinson's disease on levodopa therapy and with Helicobacter pylori infection display worse motor control than those without Helicobacter infection. Eradication of the infection improves levodopa response in Parkinson's disease, likely as a consequence of an increased oral pre-systemic bioavailability of levodopa, likely to be explained by reduced Helicobacter-dependent levodopa consumption in the stomach. In addition, small intestinal bacterial overgrowth may also have an impact on the therapeutic setting for levodopa treatment but is less well established.

conclusionEradication of Helicobacter pylori improves levodopa bioavailability resulting in improved motor control. Eradication of Helicobacter should be considered in patients with poor symptomatic control and considerable motor fluctuations.

Indexed as

Helicobacter pyloriDopamine AgentsHelicobacter InfectionsHumansLevodopaParkinson DiseaseDopamine AgentsLevodopainflammationlevodopamicrobiomeParkinson’s diseasepharmacodynamics

Identifiers

PMID33164946
PMCPMC7990449
OpenAlexW3095937410

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.