Helicobacter pylori infection is associated with a poor response to levodopa in patients with Parkinson’s disease: a systematic review and meta-analysis

Background Helicobacter pylori (HP) infection has been reported to be associated with increased severity of Parkinson's disease (PD) and have negative effects on drug response in patients. We aimed to investigate the influence of HP infection on patients with PD using a systematic review and meta-analysis approach. Methods PubMed and EMBASE databases for relevant articles published before October 2020 were searched. Two authors independently screened records, extracted data, and evaluated the quality of the included studies. The odds ratios (ORs) or standardized mean differences (SMDs) with their corresponding 95% confidence intervals (CIs) were used to calculate the pooled results by employing a random or fixed-effects model. Sensitivity analyses were conducted, and potential publication bias was assessed. Results A total of 13 studies were included in our meta-analysis. Overall, PD patients with HP infection had significantly higher levodopa equivalent daily dose (UPDRS) motor scores (SMD = 0.266; 95% CI 0.065–0.467; P = 0.009) and more units of levodopa equivalent daily dose (LEDD) (SMD = 0.178; 95% CI 0.004–0.353; P = 0.046) than those of patients without HP infection. Additionally, the time to achieve ‘ON’ state was significantly longer (SMD = 0.778; 95% CI 0.337–1.220; P = 0.001) and the duration of ‘ON’ state was significantly shorter (SMD = −0.539; 95% CI = −0.801 to −0.227; P = 0.001) in patients with HP infection than in those without HP infection. Conclusion Our pooled results of this meta-analysis demonstrated that HP infection was associated with worse motor symptoms, higher LEDD, and worse response to drugs in patients with PD. This evidence emphasizes the importance of considering subsequent eradication of HP infection in patients with PD.