Hypothesis / aims of study
Hypotheses
1) Men with lower urinary tract symptoms, when categorized by 24 hour voided volume, fall into distinct groups that may require different approaches to diagnosis and treatment.
2) Men with polyuria have a more benign underlying condition when compared to those with oliguria.
Study design, materials and methods
In this IRB approved study, an online database was queried to identify patients who completed a 24-hour bladder diary (24HBD) and the Lower Urinary Tract Symptoms Score (LUTSS) questionnaire from 2015 through 2019 using a mobile app* [1]. Data from the LUTSS and 24HBD were contemporaneously matched within a two-week period, provided that there was no change in symptoms or treatment. For multiple 24HBD and/or LUTSS, only the first recorded set was analyzed. Additional relevant information including age, gender, primary and secondary clinical diagnosis, uroflow (Qmax), post void residual urine (PVR), and voided volume were obtained from the EMR. Male patients who had incomplete or inaccurate recording of entries, or a primary clinical diagnosis of stress incontinence were excluded. In addition, our primary interest was in the LUTSS diagnosis: BPH, OAB, Nocturia, Stricture. Diagnoses that did not fit these categories were grouped into “Other.”
This cohort was then divided into three groups based on the 24HBD: polyuria (>2.5 L/24 H), oliguria (<1L/24 H) and normal (>1 -< 2500 L/24 H) [2]. This data was analyzed via the SPSS statistics software utilizing a one-way ANOVA looking at LUTS scores, bladder diary data, and urodynamic data between the three urinary groups. In addition, independent two tailed sample t-tests were run comparing the polyuria and oliguria groups. The p-value was considered significant when it was ≤.05. A more detailed breakdown of the 24HBD, LUTSS, and Urodynamic variables is listed in table 1.
Results
504 patients (331 men and 173 women, mean age 59 SD 18) completed the LUTSS questionnaire and contemporaneous 24-hour bladder diary. After applying our exclusion criteria, there were 331 men (mean age 61.5, SD 18.7). Of these,128 patients had contemporaneous Q and PVR data inputted. Results of a one-way ANOVA test comparing the three urinary groups across LUTS, 24HBD, and Urodynamics is presented in Table 1. Results of two tailed independent sample t-tests comparing oliguria and polyuria groups are also presented in Table 1.
Interpretation of results
Our data provides strong evidence that, when categorized by 24 hour voided volume, men with LUTS fall into distinct phenotypes based on clinical characteristics. The differences are most notable between the polyuria and oliguria group. Those with oliguria were older (64 vs 55 yrs), had lower 24H VV (767 vs 3475 mL), lower MVV (205 vs 428 mL) and lower Qmax (9 vs 18 mL/S).
On the other hand, the data suggests that those with polyuria have less severe underlying pathology and, in some instances may have no underlying condition – they may just drink too much because they think it is healthy to do so. An important clinical corollary is that behavioral modification may play a larger role in the treatment of these patients than those with oliguria who likely need a more aggressive approach to diagnosis and treatment.
We expected that those with polyuria would have less severe symptoms when compared to those in the oliguria group. However, there was no difference at all (between the polyuria, oliguria and normal groups) with respect to symptom severity or bother as measured by the total LUTSS or any of its sub scores. This data suggests that symptoms are a severity of underlying pathology in this subpopulation of men.