Impaired detrusor contractility is the pathognomonic urodynamic finding of multiple system atrophy compared to idiopathic Parkinson's disease.

INTRODUCTION: To investigate differences in urodynamic parameters between two groups: Parkinson's disease (PD) and multiple system atrophy (MSA) patients.

METHODS: A retrospective study was performed in patients with PD and MSA who presented to three referral centers between 2005 and 2012. Patients referred to the urology department for lower urinary tract symptoms underwent urodynamic studies. Patients with other rare or ambiguous subtypes of PPS, urinary tract infection, urinary stones, or other neurogenic conditions were excluded from the analysis.

RESULTS: A total of 581 consecutive patients (359 men and 222 women) were analyzed. The mean patient age was 69.2 (SD, 9.3) years. Among these patients, 390 (64.3%) had PD, and 191 (31.5%) had MSA. Patients with MSA showed a statistically significantly decreased maximal flow rate and increased post-void residual urine volume compared with patients with PD (P range, <0.001-0.005). In addition, voiding failure occurred more frequently in patients with MSA than in those with PD (odds ratio [OR] = 1.9; 95% confidence interval [CI], 1.26-2.73). Patients with MSA showed a higher prevalence of low-compliance (P = 0.001), decreased bladder contractility (P < 0.001), and an increased rate of voiding failure (P = 0.001). In patients with MSA, decreased detrusor contractility was more prominent in the cerebellar ataxia predominant subtype (MSA-C; P = 0.038). Multivariate analysis showed that the MSA subtype was the only independent risk factor for impaired detrusor contractility (men, OR = 2.692; P = 0.006; women, OR = 2.965; P = 0.007).

CONCLUSION: Impaired detrusor contractility was the pathognomonic urodynamic finding that distinguished MSA from PD.