AbstractThis study aimed to evaluate the clinical variations in patients with Parkinson’s disease (PD) with (PDRBD) or without REM sleep behaviour disorder (RBD) (Non-RBD), and PDRBD patients were classified into Confirmed-RBD (definite diagnosis with polysomnography, PSG) and Probable-RBD (without PSG re-confirmation). The clinical difference between the groups of patients was measured as an odds ratio (OR) or standardized mean difference (SMD, Cohen d). A total of 31 articles with data from 5,785 participants were obtained for our analysis. Overall, the occurrence of Confirmed-RBD was more frequent in male patients (OR = 1.25; p = 0.038), elderly patients (SMD = 0.25; p = 0.000), and patients with longer disease duration (SMD = 0.30; p = 0.000), increased Hoehn-Yahr scale (SMD = 0.30; p = 0.000), and higher UPDRS-III score (SMD = 0.38; p = 0.002). On the other hand, the frequency of Probable-RBD was increased with disease duration (SMD = 0.29; p = 0.000), Hoehn-Yahr scale (SMD = 0.30; p = 0.000), and UPDRS-III score (SMD = 0.26; p = 0.001). Our study indicate that PDRBD patients may have different clinical features compared to patients with Non-RBD.