Parkinson's disease may worsen outcomes from coronavirus disease 2019 (COVID-19) pneumonia in hospitalized patients: A systematic review, meta-analysis, and meta-regression

Background: Parkinson's Disease (PD) is among one of the common comorbidities in older patients. People with PD may be more vulnerable to severe pneumonia, due to the impairment of pulmonary function. Currently, the association between PD and COVID-19 is not yet established. This study aims to analyze the relationship between PD and in-hospital outcomes of COVID-19. Materials and methods: We systematically searched the PubMed and Europe PMC database using specific keywords related to our aims until December 25th, 2020. All articles published on COVID-19 and Parkinson's Disease were retrieved. The quality of the study was assessed using the Newcastle Ottawa Scale (NOS) tool for observational studies and Joanna Briggs Institute (JBI) Critical Appraisal Tools for cross-sectional studies. Statistical analysis was done using Review Manager 5.4 software. Results: A total of 12 studies with 103,874 COVID-19 patients were included in this meta-analysis. This metaanalysis showed that Parkinson's Disease was associated with poor in-hospital outcomes [[OR 2.64 (95% CI 1.75-3.99), p < 0.00001, I-2 = 81%] and its subgroup which comprised of severe COVID-19 [OR 2.61 (95% CI 1.98-3.43), p < 0.00001, I-2 = 0%] and mortality from COVID-19 [RR 2.63 (95% CI 1.50-4.60), p = 0.0007, I-2 = 91%]. Meta-regression showed that the association was influenced by age (p = 0.05), but not by gender (p = 0.46) and dementia (p = 0.23). Conclusions: Extra care and close monitoring should be provided to Parkinson's Disease patients to minimize the risk of infections, preventing the development of severe and mortality outcomes.