Lower urinary tract dysfunction is frequent in patients with multiple sclerosis (MS) and has not only a major impact on quality of life, but may also be responsible for an increased risk of upper urinary tract (UUT) damage. Urodynamic risk factors for UUT damage in neurologic patients were previously described (1). Nevertheless, there is no consensus regarding optimal urological follow-up of patients with MS, especially considering referral for urodynamic investigation (UDI). This study aimed to assess clinical parameters potentially predicting urodynamic risk factors for UUT damage.

We retrospectively reviewed 201 patients with MS referred for primary neuro-urological work-up including UDI, from August 2009 to February 2020. Clinical parameters considered were age, sex, duration and clinical course of MS, Expanded Disability Status Scale (EDSS), and number of lower urinary tract symptoms (LUTS). We assessed urodynamic parameters including maximum cystometric bladder capacity, bladder compliance, detrusor overactivity, detrusor sphincter dyssynergia, maximum flow rate, maximum voiding detrusor pressure, detrusor pressure at maximum flow rate, voided volume, and post void residual. Data were analyzed in Stata (StataCorp LLC, Texas, USA) for our variables of interest using chi-square test, t-test, and logistic regression methods. Data are presented as mean +/- standard deviation. A p-value < 0.05 was defined as significant.

Most patients were female (69%), mean age was 51.5 +/- 11.5 years old, mean age of MS onset was 34.9 +/- 10.3 years and mean disease duration was 17.4 +/- 9.8 years. At primary neuro-urological work-up, most of the patients had relapsing-remitting MS (61%), were able to walk without assistance (55%), and mean EDSS was 4.1 +/- 2.1. Most of the patients voided spontaneously (90%), and had no bladder medication (85%). Overall, 197 (98%) of the 201 patients had at least one LUTS, including urgency, frequency, urinary incontinence, and dysuria. In total, 31, 51, 75, and 40 patients presented 1, 2, 3, or 4 LUTS, respectively. The mean amount of LUTS was 2.6 +/- 1.0. Urinary incontinence was present in 63% of patients. Presence of urodynamic risk factors for UUT damage, including bladder compliance < 20 mL/cmH2O, maximum storage detrusor pressure > 40 cmH2O, detrusor overactivity (DO) combined with detrusor sphincter dyssynergia (DSD), and vesico-uretero-renal reflux was assessed. A significant relationship was found between EDSS and the presence of at least one urodynamic risk factor for UUT deterioration (odds ratio = 1.33; 95% CI = 0.97-1.82; p = 0.08). A significant relationship was also found between male gender and the presence of urodynamic risk factors (odds ratio = 0.43; 95% CI = 0.22-0.85; p = 0.01) as well as the number of LUTS (odds ratio = 1.46; 95% CI = 1.06-1.99; p = 0.02) (Table 1). All other clinical parameters were not significantly associated with urodynamic risk factors for UUT damage. Using the previously described EDSS cutoff of 5.0 to detect at least one urodynamic risk factor for UUT deterioration, a sensitivity of 40% and a specificity of 76% were achieved. By reducing the EDSS cutoff to 4.0, sensitivity rises to 60% and specificity decreases to 69%. By combining EDSS ≥ 5.0 with a number of LUTS ≥ 3, the sensitivity rises to 78% but the specificity decreases to 27%. Therefore, a nomogram combining an EDSS ≥ 5, male gender, and the number of LUTS was elaborated (Figure 1).

This study found that higher EDSS, male gender, and higher number of LUTS are significantly associated with the prevalence of urodynamic risk factors for UUT damage. Another research group have found an EDSS cutoff of 5.0 to be able to detect almost 90% of the patients at risk for UUT damage with a false positive rate of < 50% (2). In our population, this parameter alone doesn’t allow a pragmatic, risk-dependent stratification to identify patients requiring further neuro-urological assessment and treatment. This difference might be mainly influenced by the fact that our population is composed by patients with a less severe neurologic disease (EDSS 4.1 +/- 2.1 vs 5.1 +/- 1.9). The idea of creating a nomogram combining an EDSS ≥ 5, male gender, and the number of LUTS seems interesting in order to stratify patients individual risk of significant urodynamic risk factors.

Higher EDSS is significantly associated with urodynamic risk factors for upper urinary tract damage, nevertheless EDSS alone is not sufficient to choose which patient needs a urodynamic investigation. EDSS associated with other clinical findings, including number of LUTS and male gender, seems to lead to a better clinical decision. Prospective trials and larger study population are needed in order to confirm this assumption.

Panicker, JN, Fowler, CJ, Kessler, TM. Lower urinary tract dysfunction in the neurological patient: Clinical assessment and management. Lancet Neurol 2015; 14: 720–732.
Ineichen BV, Schneider MP, Hlavica M, Hagenbuch N, Linnebank M, Kessler TM. High EDSS can predict risk for upper urinary tract damage in patients with multiple sclerosis. Mult Scler 2017:1352458517703801.