Urinary incontinence is part of the classical symptom triad in normal pressure hydrocephalus (NPH), and greatly affects patient and care-taker quality of life. 45-95% of patients with NPH report urinary symptoms (1). However, data for characterization of urinary incontinence in NPH, improvement after shunt surgery and associations with demographic and clinical factors is scarce (2). Research in this area is important given the prevalence of this pathology and the lack of assessment by urologists in the majority of the cases.

The aim of this study was to determine the prevalence of urinary incontinence in patients with a diagnosis of NPH at our institution, as well as to identify risk factors associated with these symptoms, and to evaluate post-surgical urinary symptoms improvement.

An observational study was performed after approval by the institutional ethics committee. We reviewed the medical records of all patients diagnosed with NPH at our institution between 2016 and 2022, where the ICIQ-UI-SF questionnaire was applied at diagnosis and post-operatively. Sociodemographic and clinical information was also obtained.

Data was collected by the researchers in a secure RedCap database. Descriptive and bivariate analyses were performed to determine the statistically significant variables associated with NPH and shunt surgery. Statistical analysis was performed with Stata 17.

We found 117 patients diagnosed with NPH of which 75 underwent shunt surgery, 55 of these patients had a follow-up record. The mean age was 78.7 years (SD 7.1); 62% were older than 80 years (n = 53). 69.2% of patients were male (n = 81). For the primary outcome, 96 patients with a diagnosis of NPH had urinary incontinence at diagnosis, for a prevalence of 82.1%, with an average ICIQ of 10.6/21 (SD 6.5). 46.9% of patients had urgency urinary incontinence (n = 45), 5.2% stress incontinence (n = 5) and 25% mixed incontinence (n = 24). (Table 1). 

After surgical management during the first postoperative year, an improvement in the ICIQ score was observed in 83.6% of the patients (n = 46). However, of these, 10.9% presented a deterioration of the score at post-baseline follow-up (n = 5). 

In the analysis of measures of association, the following factors were found to facilitate an improvement in the ICIQ score postoperatively: obesity (OR: 14.4, p = 0.0036) and urgency  urinary incontinence (OR: 7.2, p = 0.021), age < 80 years (OR: 1.29, p = 0.75), and male gender (OR: 0.54, p = 0.46). As for the possibility of presenting urinary symptomatology at the time of diagnosis of NPH, obesity stands out with a positive association (OR: 1.38, p = 0.52). (Table 2).

Urinary incontinence prevalence was within ranges described previously in literature, nonetheless with a lower percentage of patients presenting urgency urinary incontinence than expected (57-75%) (2). Furthermore, several patients presented with either mixed incontinence or stress incontinence which could be related to gender or age-associated risk factors. 

Most patients improved on ICIQ scores postoperatively (83.6%) after shunting as expected. With statistical significance, patients with urgency urinary incontinence may were found to have a strong association to better outcomes for ICIQ improvement postoperatively, possibly due to physiological factors such as changes in cerebrospinal fluid dynamics or other factors that warrant further study.

Incontinence findings at diagnosis are similar to those reported in the literature. We also found an important post-operative improvement in urinary incontinence after the shunt surgery. 30% of patients with NPH and urinary incontinence had either mixed or stress incontinence, highlighting the importance of a multidisciplinary approach for the management of these symptoms by urology and neurology. We found few statistically significant associations, signaling the need for continued research in this field with larger, prospective studies. It also shows the importance of urology involvement in the follow-up of these patients.

Klausner AP, Robinson SP. Incontinence and lower urinary tract symptoms in normal pressure. Adult Hydrocephalus. 2014 Feb 6:80.
Echavarría LG, Gallego-Mejía A, Londoño MG, Merino-Correa SC. Efectos de las lesiones del sistema nervioso sobre la fisiología de la micción. Revista CES Medicina. 2019;33(3):182-91.