Behavioral modification is recommended as an initial management strategy in women with a clinical diagnosis of overactive bladder (OAB). This study was done to determine the magnitude and clinical characteristics of the subpopulation of women with LUTS for whom fluid restriction would be a useful strategy.

In this IRB approved study, an online database was searched for patients with persistent LUTS who completed a 24 hour bladder diary (24HBD) and the Lower Urinary Tract Symptom Score (LUTSS) from 2015 through 2019 using a mobile app*[1]. Data from patients who completed a LUTSS and a 24HBD within a two-week period were contemporaneously matched, excluding patients with any changes in symptoms or treatment, incomplete or inaccurate data entries, or a primary clinical diagnosis of stress incontinence. The earliest recorded set was analyzed when multiple 24HBD and/or LUTSS entries were present. 504 patients completed the LUTSS questionnaire and contemporaneous 24HBD. Of these, 134 women with an OAB score greater than or equal to 8 had proper data entry. Of these 134 women, 46 had urodynamic data available. Polyuria was defined as (>2.5 L/24 H), oliguria (<1 L/24 H) and normal (1 to 2.5 L/24 H) [2]. Table 1 lists the LUTSS, 24HBD, and urodynamic data variables of interest.

Table 1 displays the results of a one-way ANOVA test comparing the three urinary groups across the LUTS questionnaire, 24HBD, and urodynamic parameters. Results of the two-tailed independent sample t-tests directly comparing oliguria and polyuria groups are also presented in Table 1. Of this cohort, 44 had primary clinical diagnosis data available: 16 had a diagnosis of OAB, 1 with Nocturia, 3 with UTI, and 24 that were classified as "Other."

Our data demonstrates that when categorized by 24 hour voided volume, women with LUTS fall into distinct phenotypes based on clinical characteristics.

There were several significant factors of clinical importance between the polyuria and oliguria groups. Data from the LUTSS questionnaire shows that the scores for LUTS, Storage, OAB, and Incontinence were greater in the oliguria group. Diary data showed that the parameters for 24H VV, MVV, total urgency voids, total difficulty voids, number of nighttime voids, and total voids were significantly lower in the oliguria group. Lastly, urodynamic data showed that the Qmax and Voided Volume parameters were significantly lower in the oliguria group, demonstrating greater severity of underlying conditions.

As expected, the LUTSS questionnaire scores were greater in the oliguria group while the 24HBD and urodynamic data had parameters that were lower for this group. Next, we expect those with oliguria to have more severe symptoms when compared to those in the polyuria group. For most categories of the LUTSS questionnaire, greater scores were associated with the oliguria group. This data suggests that the LUTSS may potentially correlate with the severity of underlying pathology in this sample of women.

Similarly, we expect to see more incontinent voids and difficulty voiding episodes in the oliguria group when compared to the polyuria group. The data shows otherwise. There are a couple of plausible explanations for these differences. Polyuria patients have more opportunities to void than oliguria patients, in turn, allowing for a greater opportunity for difficulty voiding episodes. On the other hand, oliguria patients may void as soon as they sense the urge, which is in itself a form of self-behavior modification. Thus, polyuria patients are more likely to benefit from behavior modification therapy. Also, patients with oliguria may restrict fluid intake to reduce the impact that their underlying pathology has on their symptoms.

Voiding diaries reveal that a large fraction of women presenting with LUTS exhibit polyuria (25%). These women are symptomatically distinguishable from those with oliguria (13%) and are the group in which fluid restriction is more likely to be efficacious. This highlights the essential role of a 24HBD and LUTS questionnaire in the behavioral management of OAB for patients.

Blaivas JG, Tsui JF, Mekel G, et al. Validation of the lower urinary tract symptom score. The Canadian Journal of Urology. 2015 Oct;22(5):7952-7958.
Hashim, H., Blanker, M. H., Drake, M. J., Djurhuus, J. C., Meijlink, J., Morris, V., Petros, P., Wen, J. G., & Wein, A. (2019). International Continence Society (ICS) report on the terminology for nocturia and nocturnal lower urinary tract function. Neurourology and urodynamics, 38(2), 499–508.