Introduction: Lower urinary tract symptoms (LUTS) are common in individuals with multiple sclerosis (MS), and can have a significant impact on quality of life (QoL). Prevalence of LUTS in MS ranges from 32% to 96.8%, including storage or voiding symptoms or a combination of these. Post-void residual (PVR) is a very well-tolerated, non-invasive test for evaluating voiding dysfunction. The aim of the current study was to describe the distribution of PVR volumes across MS subjects with and without LUTS and to examine relationships between storage symptoms, voiding symptoms, and PVR. Methods: A large group of subjects (N = 501) completed a questionnaire on LUTS (current bladder management, number of urinary tract infections in the last year and urological investigations). A bladder ultrasound for PVR was performed and data were collected. We used Chi-Square and the Mann-Whitney non-parametric tests respectively for categorical and continuous variables in order to assess differences between symptomatic and asymptomatic groups. The differences of PVR by LUTS status were explored using the Mann-Whitney nonparametric test for independent samples. Results: Overall mean PVR was 132.4 mL (PVR > 100 ml was considered an abnormal residual urine volume). Based on the LUTS questionnaire, 43 subjects (8.6%) were asymptomatic, while 458 subjects (91.4%) reported at least one LUTS. Storage-related symptoms were reported by 87.2% of subjects (437) and 65.1% (326) reported at least one voiding-related symptom. Two-third of subjects (66.5%) reported three or more LUTS. There was a statistically significant association between the presence of LUTS and the number of infections reported (p = 0.0015). The symptomatic group had significantly higher PVR than the asymptomatic group (p = 0.011). PVR significantly correlated with male gender, disability level and a progressive disease course. Conclusion: Results showed a high prevalence of LUTS in subjects with MS and that storage symptoms are predominant. There was an association between the presence of LUTS and a progressive disease course. The relationship between LUTS, higher PVR and the severity of disease course indicates that a comprehensive clinical evaluation should include an assessment of both neurological and micturition disorders and, importantly, PVR should be measured at every clinical assessment, despite the presence or absence of LUTS.
