Appendectomy Does Not Increase the Risk of Future Emergence of Parkinson's Disease: A Meta-analysis

Objective To explore the impact of appendectomy history on emergence of Parkinson's disease (PD). Background Although there are several studies to investigate the relationship between appendectomy history and emergence of PD, the results are still controversial. Methods We performed a comprehensive electronic search of the literature (the Cochrane Library, PubMed, and the Web of Science) up to April 2020 to identify studies that had employed databases allowing comparison of emergence of PD between patients with and those without appendectomy history. To integrate the impact of appendectomy history on emergence of PD, a meta-analysis was performed using random-effects models to calculate the risk ratio (RR) and 95% confidence interval (CI) for the selected studies, and heterogeneity was analyzed using I-2 statistics. Results Four studies involving a total of 6 080 710 patients were included in this meta-analysis. Among 1 470 613 patients with appendectomy history, 1845 (.13%) had emergences of PD during the observation period, whereas among 4 610 097 patients without appendectomy history, 6743 (.15%) had emergences of PD during the observation period. These results revealed that patients with appendectomy history and without appendectomy had almost the same emergence of PD (RR, 1.02; 95% CI, .87-1.20; P = .83; I-2 = 87%). Conclusion This meta-analysis has demonstrated that there was no significant difference in emergence of PD between patients with and those without appendectomy history.