Meta-analysis on the prevalence of REM sleep behavior disorder symptoms in Parkinson’s disease

BACKGROUND: Our study was aimed to evaluate the risk of a selected non-motor symptom, namely rapid eye movement behavior disorder (RBD) symptoms, among patients with newly diagnosed Parkinson disease compared with health controls. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for meta-analysis and Cochrane manual were followed. Studies on RBD symptoms and PD were searched using PubMed, Embase, Web of Science and Cochrane library databases. All studies were published before August 3(rd), 2016. Eligible studies were those that reported a prevalence of RBD symptoms among newly diagnosed PD and health control. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by random-effected models. Heterogeneity across studies was assessed using Cochran Q and I(2) statistics. RESULTS: We identified eight studies including 2462 PD patients and 3818 health controls. The overall prevalence of RBD symptoms in PD was 582/2462 (23.6%) compared to 131/3818 (3.4%) in control. And the pooled OR was 5.69 (95% CI 3.60 to 9.00; p = 0.001) with a moderate heterogeneity I(2) = 70.5%. After excluding the study of low weight, the overall polled OR was 3.54 (95% CI 2.77 to 4.52; p < 0.00001) and the heterogeneity was completely eliminated (I(2) = 0%). CONCLUSIONS: RBD symptoms are common non-motor symptoms of PD, and people with PD are at a higher risk of developing RBD. Further studies are needed to understand the natural history of RBD symptoms in PD and its etiological and clinical implications.