Jerzy B. Gajewski, Department of Urology, Dalhousie University, QEII Health Science Centre, HI Site, 1225B-1796 Summer St, Halifax, NS, B3H 3A7 Canada. e-mail: email@example.com
Study Type – Therapy (review)
Level of Evidence 4
What's known on the subject? and What does the study add?
It is known that overactive bladder (OAB) symptoms correlate weakly with urodynamic findings, especially in female patients.
The study shows that OAB symptoms also correlate weakly with urodynamic findings in male patients. More than third of male patients with OAB symptoms had evidence of BOO. The study finds that a pressure flow study is of benefit in the evaluation of this group of patients.
• To assess the correlation between overactive bladder (OAB) symptoms with urodynamic (UD) findings in men.
PATIENTS AND METHODS
• We conducted a retrospective study of all UD studies involving men with OAB symptoms.
• All UD studies were carried out at a single centre from 1994 to 2009 and were reported by one urology specialist.
• There were 668 UD reports included in the final analysis. All patients had symptoms of urgency with or without urgency incontinence (UI).
• There was a weak correlation between OAB symptoms and UD findings.
• All storage symptoms, except frequency, correlated with a finding of detrusor overactivity (DO).
• Severity of urgency correlated inversely with a finding of bladder outlet obstruction (BOO).
• Both nocturia and frequency correlated inversely with maximum cystometric capacity.
• More than 75% of patients had concomitant voiding symptoms. Severity of voiding symptoms (slow stream and incomplete emptying) correlated inversely with documentation of DO. Voiding symptoms were predictors of BOO, while severe urgency was a negative predictor for BOO.
• There were weak correlations between OAB symptoms and UD findings. Most men with OAB symptoms had concomitant voiding symptoms and more than a third (43%) of these had evidence of BOO.
• A pressure flow study is of benefit in the evaluation of patients with OAB symptoms.
The ICS defines overactive bladder (OAB) syndrome as urgency, with or without urgency incontinence (UI), usually with frequency and nocturia . The prevalence of OAB in both genders is reported to range between 12% and 53% [2,3]. UI is a common and distressing condition known to adversely affect quality of life .
The role of urodynamic (UD) studies in the initial evaluation of men with OAB is unclear, but many physicians perform a UD study after the failure of conservative medical management. Patients who are considered for more invasive interventions with intravesical injection, sacral neuromodulation or bladder augmentation are usually subjected to UD studies. Previous studies, especially in women, have shown that the bladder is an unreliable witness, meaning that symptoms correlate weakly with UD observations . Other studies have shown that there is no correlation between detrusor overactivity (DO) and OAB symptoms , but most of these studies were done in female patients, recruited small numbers of patients, or did not include pressure flow study (PFS) results.
The primary objective of the present study was to assess the correlation between OAB symptoms and UD findings in men. The secondary objective was to report the predictors for BOO and DO in this group of patients.
PATIENTS AND METHODS
We carried out a retrospective analysis of all UD studies involving men with OAB symptoms from 1994 to 2009 in one centre. The study was approved by our institutional ethics board. All patients were interviewed by a physician before the UD study and the symptoms were graded from 0 to 3 (Table 1). All patients had symptoms of urgency with or without UI. The graded symptom questionnaire allowed the assessment of each symptom and then the correlation with all UD variables. UD studies were water-based and were done in a quiet, specially equipped room by an experienced specialist urology nurse [1,7]. Patients were referred for UD study because of persistent OAB symptoms or having additional LUTS. UD studies consisted of free flow uroflometry, medium rate conventional filling cystometry in the semi-sitting position, a stress urine leak test and a PFS. A transurethral 7F double-lumen catheter was used to measure vesicle pressure. Abdominal pressure was monitored simultaneously with a rectal balloon catheter. Peri-anal surface electromyography activity was recorded during both the filling and pressure flow phases of the UD study. It is our usual practice to continuously interact with patients during the UD study in order to reproduce the symptoms. Almost all patients underwent two UD tests to confirm the findings. All UD findings were reported by a single urologist (J.G.) who specializes in the management of patients with voiding dysfunction.
Table 1. LUTS grading during patient interview
Mild (can continue usual activity)
Moderate (shorten usual activity)
Severe (stop all activity)
Mild (straining to void)
Moderate (Interrupted stream)
Patients with stress UI, neurogenic disorders, previous lower urinary tract surgery, prostate cancer, previous pelvic radiation therapy, or who were using catheterization were excluded from the study. Patients with poor bladder compliance, poor contractility or an incomplete UD study were also excluded. UD studies were not performed in patients with a positive urine dipstick.
All LUTS and UD terminology in the present report are consistent with the ICS standardized terminology report . Storage symptoms (urgency, UI, frequency and nocturia) and voiding symptoms (slow stream and incomplete emptying) were compared with free flow variables (maximum flow rate (MFR), voided volume, post-void residual urine volume (PVR), filling cystometry (DO, maximum cystometric capacity [MCC]) and PFS (BOO). Any involuntary detrusor contractions during filling cystometry were considered to indicate DO. BOO was defined using the BOO index (BOO index = PdetQmax− 2x Qmax, where Qmax is maximum urinary flow rate and Pdet is detrusor pressure) .
Spearman correlation coefficients were determined to evaluate the correlation between OAB symptoms and UD findings. Independent factors that might be associated with changes in MCC were assessed using univariate and multivariate linear regression analysis. To determine the independent factors for DO and BOO, univariate and multivariate logistic regression analysis were used. Statistical analysis was carried out using spss V17 software (Chicago, IL, USA). A P value <0.05 was considered to indicate statistical significance and the statistical results were two-sided.
Out of 1315 UD studies in men with LUTS, 668 UD reports fulfilled the inclusion criteria and were included in the final analysis. The mean (range) age of patients was 67 years (30–90) and the median (range) duration of symptoms was 12 (3–280) months. All patients had symptoms of urgency, with or without UI (100%). The presence of frequency was reported in 612 patients (91%), nocturia in 537 (80%), UI in 314 (47%), slow stream in 540 (80.1%) and incomplete emptying in 517 (77%). DO was documented in 258 patients (38.6%) and 293 patients (43.9%) had evidence of BOO during PFS (Fig. 1).
The severity of storage symptoms (urgency, UI and nocturia) correlated weakly and positively with the presence of DO on filling cystometry. The correlation was somewhat stronger with UI (r= 0.21) than with urgency (r= 0.14). The severity of urgency correlated weakly and inversely with the presence of BOO (r=−0.16). Both nocturia and frequency correlated weakly and inversely with the MCC (r=−0.17). Severe nocturia correlated weakly and inversely with MFR and voided volume (r=−0.18 and −0.15, respectively). The severity of voiding symptoms (slow stream and incomplete emptying) correlated weakly and inversely with the presence of DO (r=−0.11 and −0.103, respectively). Slow stream correlated weakly and inversely with MFR (r=−0.21) and voided volume (r=−0.15). There was no correlation between OAB symptoms and PVR (Table 2).
Table 2. Spearman correlation coefficients between OAB symptoms and UD findings
The MCC was inversely correlated with age and the severity of nocturia or frequency (SC −0.08, −0.162 and −0.182, respectively). Multivariate analysis showed that age and UI were significant predictors of DO while slow stream was not, with odds ratios (ORs) of 1.04, 2.3 and 0.6, respectively. Age, slow stream and incomplete emptying were positive predictors of BOO with ORs of 1.02, 2.10 and 4.5, respectively. The severity of urgency was a negative independent predictor of BOO with an OR of 0.4 (Table 3).
Table 3. Univariate and multivariate analysis for DO, BOO and MCC
Recent studies suggest that the true prevalence of OAB might be greater than that reported previously . Men >40 years may complain of OAB symptoms, with a prevalence of 15–60% in this age group . The rate increases to 80% in men >80 years of age . A recent population-based survey showed that the syndrome itself is dynamic in nature and up to 30% of community-dwelling elderly men with no or mild symptoms will have clinically significant symptoms within 2 years .
The ICS defines urgency as a sudden compelling desire to void that is difficult to defer. UI is defined as complaints of urine leakage accompanied or proceeded by urgency . These symptoms are the cornerstone for diagnosis of OAB. DO is thought to be the main cause of the OAB symptoms . In the present study there was a positive and significant association between the severity of urgency and the documentation of DO, but this correlation was weak. The fact that most patients with UI have mild symptoms (can continue their usual activities) may contribute to the weak correlation with DO. In univariate analysis, urgency was an independent predicting factor for the presence of DO (OR 2.2). UI was an independent factor for DO in both univariate and multivariate analysis (ORs 2.8 and 2.3, respectively). It has been reported previously that there is no correlation between DO and OAB symptoms . Tong  examined 84 male patients with LUTS and reported that patients with DO tend to have less urgency, because of small voiding volumes or abnormal bladder sensation. However, Hashim and Abrams  recently showed that urgency and UI are good predictors of the presence of DO, especially in men (91% in men vs 57% in women). By contrast, the present study shows that the severity of urgency was significantly and inversely related to the presence of BOO. Patients with documented obstruction on PFS have a milder form of urgency and subsequently OAB symptoms. In logistic regression analysis, this association was present in both univariate and multivariate analysis (OR 0.4). More than 75% of our study population had associated voiding symptoms and 43% of them had evidence of BOO. Verdejo et al. reported that, in 350 elderly men, the most frequent UD finding associated with OAB symptoms was BOO (41%). In older patients with LUTS, voiding symptoms are very common, but storage symptoms are the most troublesome and have a major effect on quality of life .
The ICS does not specify a normal range for voiding frequency during the day. Frequency is a complaint of voiding too often during the day by the patient. Voiding frequency more than 8 times per day has been found to become bothersome . In the patients in the present study, there was a weak but significant inverse correlation between severity of frequency and bladder capacity. Frequency did not correlate with the presence of DO or BOO. In a retrospective review of UD findings of 12 men and 38 women with OAB symptoms, Sekido et al.  reported that patients with frequency and incontinence had a significantly lower MCC. They reported that there was no association between OAB symptoms and the presence of DO. Hashim and Abrams  found that frequency alone was a poor predictor of DO in patients with OAB but the correlation was stronger in men than women.
Previous studies have shown that nocturia correlates with lower quality of life . The symptom of nocturia in the present study population positively correlated with the presence of DO and inversely with MCC and MFR. It is most likely that patients had a lower MFR because of a lower bladder capacity. In univariate analysis, severe nocturia was a predictor of BOO (OR 1.6). In a study of 231 elderly men with OAB symptoms and DO on UD, Shahab et al.  found an inverse correlation between severity of nocturia and MCC. A lowered afferent nerve ending threshold may contribute to this finding .
The voiding symptoms that were assessed in the present study, slow stream and incomplete emptying, inversely correlated with the presence of DO. Slow stream was a negative independent predictor for DO in both univariate and multivariate analysis. In addition, the slow stream was a positive predictor for BOO (OR 2–2.2). This finding is even more evident in older patients and age was an independent predictor of both DO and BOO. Changes in bladder wall morphology secondary to aging have been well demonstrated in both genders . Hakenberg et al.  retrospectively evaluated 95 men with LUTS suggestive of BOO. Age was the only independent predictor for the outcome in their study. They concluded that the main value of PFS and symptom score was to exclude patients who will not benefit from TURP. In an another study of 75 men with LUTS secondary to benign prostatic hypertrophy, 53% had evidence of BOO and only age was found to be a significant predictor of BOO . Shahab et al.  showed that severity of DO increased with age in men with OAB symptoms and enlarged prostate; however, most of these studies did not find a correlation between the symptoms and the UD findings [14,24].
Uroflometry and PVR estimation are simple tests that can raise the suspicion of BOO presence, but neither lead directly to a definitive diagnosis . Around 25–30% of patients with low flow rate (<10 mL/s) do not have BOO . PVR estimation has been shown to be more suggestive of detrusor failure than has BOO . PFS remains the ‘gold standard’ for diagnosis of BOO . The overall treatment efficacy of TURP has been shown to be better for patients with documented BOO than for those without BOO .
Although we found some associations between OAB symptoms and UD findings, most of these associations were weak. This indicates that the bladder in male patients with OAB symptoms is an unreliable witness. UD studies might add more information in this group of patients, especially if they failed first-line conservative management.
The present study has some drawbacks. First, the study was retrospective in nature. Secondly, the management and then the outcome were not evaluated in this group of patients. Thirdly, the symptoms were evaluated with an unvalidated questionnaire. A strength, however, is that the LUTS were recorded individually and were compared with all UD variables. The large sample size is another strength.
In conclusion, we assessed the correlations between OAB symptoms and UD findings in the largest series of male patients to date. In general, there was a weak correlation between OAB symptoms and UD findings. Most men with OAB symptoms had concomitant voiding symptoms. A significant inverse correlation of severe urgency with BOO was found. PFS could provide additional information in this group of patients, especially if they have failed initial conservative management.
We would like to thank Dr. John Downie from the Department of Urology, Dalhousie University, Halifax, NS, Canada for his help in reviewing and editing the manuscript.