Critical review of the diagnosis of prostatic obstruction

Factors influencing efficacy endpoints in clinical trials for new oral medicinal treatments for overactive bladder: a systematic literature review and meta-analysis

PURPOSE

Overactive bladder (OAB) is a symptom-based disease; therefore, clinical trials to evaluate treatments for OAB employ a range of efficacy endpoints. Since factors that influence efficacy endpoints can affect trial outcomes, their identification could aid in the design of future OAB clinical trials. We investigated factors influencing different efficacy endpoints used in clinical trials with OAB patients and examined their characteristics to determine future clinical trial strategies for new medicinal treatments for OAB.

METHODS

Data from placebo-controlled double-blind trials in patients with OAB were extracted via a systematic literature review. The integrated differences for efficacy endpoints were calculated. Heterogeneity was assessed using the Q statistic and I² statistic. Factors influencing efficacy endpoints were identified through univariate and multivariate meta-regression analyses.

RESULTS

Forty-one controlled trials were analyzed. Substantial heterogeneity between studies was observed for each efficacy endpoint (P > 0.001, I² > 70%). We found with multivariate meta-regression analysis that period of recording in a bladder diary and year of publication were significantly likely to influence the change from baseline in the mean number of urgency episodes in 24 h, year of publication and gender were significantly likely to influence the change from baseline in the mean number of micturitions in 24 h, and gender was significantly likely to influence the change from baseline in the mean volume voided per micturition. In contrast, there were no factors significantly associated with change from baseline in the mean number of incontinence episodes in 24 h.

CONCLUSIONS

We identified that change from baseline in the mean number of incontinence episodes in 24 h should serve as a relatively stable endpoint. In contrast, we identified factors influencing other endpoints, and the identified factors should be taken into account when planning and conducting future clinical trials.

Current consensus and controversy on the diagnosis of male lower urinary tract symptoms/benign prostatic hyperplasia

Traditionally, male lower urinary tract symptoms (LUTS) have been considered a synonym for benign prostate hyperplasia (BPH) because most male LUTS develops in aging men. Medical treatment should be the first-line treatment for BPH and surgical intervention should be performed when there are complications or LUTS refractory to medical treatment. Recent investigations have revealed that bladder dysfunction and bladder outlet dysfunction contribute equally to male LUTS. In the diagnosis of LUTS suggestive of BPH (LUTS/BPH), the following questions should be considered: Is there an obstruction? Are the LUTS caused by an enlarged prostate? What are the appropriate tools to diagnose an obstructive BPH? Should patients with LUTS be treated before bladder outlet obstruction is confirmed? This article discusses the current consensus and controversies in the diagnosis of LUTS/BPH.

The Use of Urodynamics Assessment Before the Surgical Treatment of BPH

Lower urinary tract symptoms (LUTS) are a common problem in men especially with aging. The International Continence Society (ICS) revealed an overall prevalence of LUTS of about two-thirds of men age 40 years and above. The treatment approach depends on accurate determination of the underlying etiology. LUTS is not unique to benign prostate enlargement (BPE) and can be secondary to other causes. In the era where quality of care is important, accurate diagnosis and counseling to meet patients' expectations is of extreme paramount. Thus, proper assessment of patients who present with BPE and LUTS should be an important part of the work up process. Accurate diagnosis and identification of the cause will help to improve quality of treatment, optimize counseling, and improve treatment outcomes. Pressure flow urodynamic studies (PFUDs) are not only important tools that help to identify the underlying causes of LUTS; it is considered the "gold standard" for diagnosis of bladder outlet obstruction (BOO) in patients with enlarged prostate [1, 2]. However, there is a continuous debate on the value of using PFUDs and its association with improved outcomes.

Noninvasive methods of diagnosing bladder outlet obstruction in men. Part 2: Noninvasive urodynamics and combination of measures

PURPOSE

Many methods have been suggested to diagnose bladder outlet obstruction, as defined by the gold standard of pressure flow studies. Difficulty arises when comparing completely different methods of diagnosing bladder outlet obstruction. A comprehensive review of the literature on the different methods used to diagnose bladder outlet obstruction by noninvasive means was performed with a view to allow such a comparison.

MATERIALS AND METHODS

A MEDLINE search was done of the published literature covering until the end of 2004 on noninvasive methods, including single measure and combinations of measures, to diagnose bladder outlet obstruction. A direct comparison of all of the different methods was made using the sensitivity, specificity, likelihood ratio, and pretest and posttest probability of diagnosing bladder outlet obstruction for each test. For many techniques these values were calculated from the data presented in the article.

RESULTS

A multitude of methods has been applied to diagnose bladder outlet obstruction. Broadly the methods were divided into nonurodynamic and noninvasive urodynamic methods. Nonurodynamic methods were considered in part 1 of the review. Part 2 considered noninvasive urodynamic techniques, such as uroflowmetry, the penile cuff, the condom method and Doppler urodynamics. A combination of single measures was also considered and the relative merits of these approaches were discussed.

CONCLUSIONS

A combination of noninvasive urodynamics and ultrasound derived measures provide promising methods of diagnosing bladder outlet obstruction. However, pressure flow studies still remain the gold standard for assessing bladder outlet obstruction.

Overactive bladder in men: special considerations for evaluation and management

Lower urinary tract symptoms (LUTS) in men may arise from a variety of underlying causes, including benign prostatic hyperplasia. LUTS may have a significant component of storage symptoms (urgency, frequency, urge incontinence) at presentation; however, the absence of overactive bladder (OAB) symptoms does not necessarily imply pure outlet obstruction nor does their presence indicate the lack thereof. Symptomatic correlates to urodynamic findings are high when considering isolated OAB symptoms. However, mixed presentations or more overtly obstructive scenarios have less correlation with baseline symptom appraisal instruments. The ideal approach for diagnosis and management is predicated on a graded approach, with more invasive evaluation withheld for those men in whom presumptive therapy fails or who present with associated complex symptoms and in whom a higher level of intervention is being considered. The increasing incidence of LUTS with age implies a partial detrusor contribution, which must be considered in the overall management schema.

Detrusor instability in men: correlation of lower urinary tract symptoms with urodynamic findings

PURPOSE

We evaluated the correlation of lower urinary tract symptoms suggestive of detrusor instability with urodynamic findings in men.

MATERIALS AND METHODS

Enrolled in our prospective study were 160 consecutive neurologically intact men referred for urodynamic evaluation of persistent lower urinary tract symptoms. All patients had storage symptoms suggestive of detrusor instability. Patients were further clinically categorized according to the chief complaint of urge incontinence, frequency and urgency, nocturia or difficult voiding. The clinical and urodynamic diagnosis in all patients as well as specific urodynamic characteristics of those with detrusor instability were analyzed according to the these 4 clinical categories.

RESULTS

Mean patient age was 61 +/- 15 years. The chief complaint was urge incontinence in 28 cases (17%), frequency and urgency in 57 (36%), nocturia in 30 (19%) and difficult voiding in 45 (28%). Detrusor instability was diagnosed in 68 cases (43%). A higher incidence of detrusor instability was associated with urge incontinence than with the other clinical categories (75% versus 36%, p <0.01). Of the patients 109 (68%) had bladder outlet obstruction, including 50 (46%) with concomitant detrusor instability. The prevalence of bladder outlet obstruction was similar in all patients regardless of the chief complaint. All other urodynamic diagnoses were also similar in the 4 clinical categories. The mean bladder volume at which involuntary detrusor contractions occurred were lower in patients with urge incontinence and frequency and urgency than in those with nocturia and difficult voiding (277.1 +/- 149.4 and 267.7 +/- 221.7 versus 346.7 +/- 204.6 and 306.2 +/- 192.1 ml., respectively, not statistically significant, p = 0.07).

CONCLUSIONS

Detrusor instability and bladder outlet obstruction are common in men with lower urinary tract symptoms. The symptom of urge incontinence strongly correlated with detrusor instability. Other lower urinary tract symptoms did not correlate well with any urodynamic findings. Therefore, we believe that an accurate urodynamic diagnosis may enable focused and more efficient management of lower urinary tract symptoms in men.

Home uroflowmetry: improved accuracy in outflow assessment

To study home uroflowmetry and to compare this method to free or "traditional" uroflowmetry in the evaluation of the patient with symptomatic benign prostatic hyperplasia (BPH), and the relationship between the values of home uroflowmetry parameters and bladder outlet obstruction (BOO). Twenty-five patients (mean age, 67 years) with symptomatic BPH were examined with home uroflowmetry, free uroflowmetry, and pressure-flow measurement. The patients were assessed using the International Prostate Symptom score; digital rectal examination; routine blood chemistry, including serum prostate-specific antigen level; urinanalysis; transrectal ultrasonography; and post-void residual urine. The 24 hr were divided into "active time" (AT) and "sleep time" (ST). AT home uroflowmetry parameters were compared to ST ones. The home uroflowmetry parameters were compared to respective ones of the free uroflowmetry as well and those obtained by pressure-flow measurement. The patients were asked about their opinion of home uroflowmetry. Home uroflowmetry was found to be a simpler and more acceptable method than free uroflowmetry. The mean Qmax of AT was significantly greater than the mean Qmax of ST, but the mean voided volume and mean voiding time of ST were significantly larger than those of AT. There was a close relationship between the mean Qmax at home and the Qmax in hospital, but the voided volume and voiding time measured in hospital were significantly larger than those at home. Home uroflowmetry provided an estimation of BOO for 46% of the patients as low if the home mean Qmax was >14 ml/sec, and as high if the home mean Qmax was <10 ml/sec. Home uroflowmetry was well accepted by the patients and gave more information than free uroflowmetry. In 46% of the cases, an estimation of BOO was obtained with home uroflowmetry.

Analysis of outcome after thermotherapy using different classifications of bladder outlet obstruction

The urodynamic profiles of 97 patients with benign prostatic hyperplasia undergoing low-energy transurethral microwave thermotherapy (TUMT) for lower urinary tract symptoms were analysed using the Abrams/Griffiths nomogram, the urethral resistance algorithm, the linPURR, Schäfer nomogram, and the CHESS classification. A significant clinical response was seen for the whole group, as shown by changes in symptom score, free flow rate, and residual urine. The best symptomatic response was identified in patients in whom obstruction was present, whatever the classification used. Only the two-dimensional CHESS classification was found to predict a group of patients with a better response in both symptoms and objective variables. Obviously, a better response from TUMT can only be predicted by a classification system that identifies the independent variables of footpoint and slope of the PURR. The CHESS classification was the only one of those studied that satisfactorily identified these two parameters and could be used as a system of case selection for this minimally invasive treatment.

Lower urinary tract symptoms, benign prostatic obstruction and the overactive bladder

Lower urinary tract symptoms (LUTS), benign prostatic obstruction (BPO), and the overactive bladder have increasing prevalence with age in both men and women (with the obvious exception). The question is, are they interrelated or independently related to age? The specific issue is whether BPO causes the overactive bladder. There are two pieces of evidence that might appear to suggest such a cause and effect. First, the overactive bladder is more common in men than in women of the same age, although physiologically, men are 5-10 years older at the same biological age. Second, the overactive bladder resolves in two-thirds of individuals after surgical interventions such as transurethral prostatectomy. The symptoms suggestive of an overactive bladder are the most troublesome, even though they may not be the most prevalent. Long-term follow-up studies with repeated urodynamic investigations have shown that the incidence of the overactive bladder and its attendant symptoms increases despite there being no deterioration in outlet obstruction over follow-up periods of 10 and 20 years. These data, and others, indicate that the situation is not as straightforward as some believe. The statement that 'the overactive bladder is secondary to BPO' cannot be made, as there are too many unanswered questions and pieces of the puzzle that do not fit. The overactive bladder is undoubtedly associated with BPO, and it leads to the most troublesome LUTS in older men. Epidemiological research, coupled with urodynamic evaluation, may provide further evidence. We also need better and more relevant models (e.g. ageing animals), together with further histological and other biological data before the waters become crystal clear.

Is bladder outlet obstruction normal in elderly men without lower urinary tract symptoms?

The aim of the present study was to correlate basic voiding parameters, including uroflowmetry, symptom score, and residual urine volume with the results of pressure-flow studies applying the Abrams/Griffith nomogram, in a series of urologically asymptomatic elderly men. Twenty-nine consecutive male volunteers (median age, 66 years) without past or present urological complaints participated. Fifteen (52%) of the 29 subjectively normal men proved to have bladder outlet obstruction (BOO). Qmax <10 mL/s had a positive predictive value of 100% in diagnosing obstruction, whereas the predictive information of higher flow rates proved very modest. No significant difference existed between obstructed and unobstructed persons at any cutoff value concerning symptom score. The sensitivity as well as the positive predictive value of a residual urine volume >50 mL was zero. It is concluded that a surprisingly high prevalence of BOO in asymptomatic elderly men was demonstrated and that the correlation between pressure flow investigations and alternative diagnostic tests, i.e., flow rate, symptom score, and residual volume was weak in this group of men. It is suggested that a possible explanation for the high frequency of BOO observed in the evaluated asymptomatic men could be that the values defining obstruction have been set too low. Neurourol. Urodynam. 18:545-552, 1999.

Improving the utility of urine flow rate to exclude outlet obstruction in men with voiding symptoms

OBJECTIVES

Many older men with voiding symptoms do not have bladder outlet obstruction (BOO) but have conditions amenable to medical treatment. If primary care providers could reliably exclude men who have BOO, then they could initiate appropriate evaluation and treatment in a substantial proportion of the remainder. Urine flow rate, although widely used, is insufficiently sensitive to exclude BOO reliably. We investigated whether the decline in flow rate with age could be utilized to improve the utility of flow rate for excluding BOO in symptomatic men, especially when combined with knowledge of the patient's postvoiding residual volume (PVR).

DESIGN

Prospective study using two patient cohorts.

SETTINGS

A Veterans Affairs urology clinic serving community-dwelling and institutionalized healthy older men.

PARTICIPANTS

111 men with voiding symptoms (mean age 72.4 +/- 9.2 years).

MEASUREMENTS

Maximum urine flow rate, measured with standard flowmeter, and PVR, measured by catheterization. BOO was determined by multichannel videourodynamic testing.

RESULTS

The sensitivity of flowrate for BOO increased significantly with age (P = .0001) and did not appear to be confounded by comorbid conditions. An algorithm incorporating age, flow rate, and PVR had a sensitivity of 90%, specificity of 43%, and accuracy of 74% in screening for BOO. The algorithm's sensitivity was better than that of flow rate alone (55%); its sensitivity was also similar to a "refer all" strategy (100%) but had improved specificity (41% vs 0%).

CONCLUSIONS

Flow rate alone is insufficiently sensitive as a screening test to exclude BOO, but a simple diagnostic algorithm using age, flowrate, and PVR was more sensitive and accurate. This algorithm allows primary care evaluation and initial management of men with voiding symptoms while potentially reducing unnecessary referrals and costs.

Prediction of prostatic obstruction with a combination of isometric detrusor contraction pressure and maximum urinary flow rate

OBJECTIVES

Because isometric detrusor contraction pressure (Piso) increases with outlet obstruction and maximum urinary flow rate (Qmax) tends to decrease with obstruction, we hypothesize that specific criteria consisting of a combination of high Piso and low Qmax may be able to differentiate obstructive from nonobstructive voiding dysfunction better than either parameter alone.

METHODS

Two hundred five men with lower urinary tract symptoms underwent uroflowmetry and videourodynamics, including cystometry, continuous outlet occlusion test, and micturitional urethral pressure profilometry. Combined threshold values of Qmax of less than 12 mL/s and Piso of 100 cm H2O or greater were used to predict obstruction, whereas threshold values of Qmax of at least 12 mL/s and Piso less than 100 cm H2O were used to predict nonobstruction.

RESULTS

Of the 205 patients, 103 (50%) were significantly obstructed and 102 (50%) were only mildly obstructed or nonobstructed. Of the total population, 151 patients (74%) were categorized by the combined flow and contractility criteria. Of the categorized patients, 141 (93%) were correctly diagnosed with regard to infravesical obstruction (sensitivity 89%, specificity 97%, positive predictive value 97%, and negative predictive value 91%).

CONCLUSIONS

A combination of Qmax and Piso criteria can predict obstructive and nonobstructive voiding dysfunctions with high positive and negative predictive values in most patients with lower urinary tract symptoms. Combining the results of uroflowmetry and isometric tests may help to guide treatment strategies that may improve the outcome of selected therapeutic options compared with strategies based on symptoms or uroflowmetry alone. Furthermore, this approach forms a basis for interpreting various noninvasive methods that have recently been introduced for the purpose of diagnosing bladder outlet obstruction.

The correlation between bladder outlet obstruction and lower urinary tract symptoms as measured by the international prostate symptom score

PURPOSE

We studied the relationship between lower urinary tract symptoms as measured by the international prostate symptom score (I-PSS) and urodynamic findings in elderly men.

MATERIALS AND METHODS

We evaluated 803 consecutive patients with lower urinary tract symptoms via the I-PSS and urodynamics with pressure-flow studies.

RESULTS

A statistically significant correlation was found between all I-PSS questions (except intermittency) and objective parameters of obstruction. However, the clinical significance of this finding is minimal because a large overlap of symptom scores exists among patients with different grades of bladder outlet obstruction. The filling component of the I-PSS correlated somewhat better with obstruction than did the voiding component.

CONCLUSIONS

It seems impossible to diagnosis bladder outlet obstruction from symptoms alone. It does not even seem possible to define subgroups in which further urodynamic examination is indicated.

The correlation between urodynamic and cystoscopic findings in elderly men with voiding complaints

PURPOSE

We evaluated the urethrocystoscopic findings and results of urodynamic studies in elderly men with voiding complaints.

MATERIALS AND METHODS

A total of 492 consecutive patients with voiding complaints underwent a standardized screening program, including transrectal ultrasonography of the prostate, urodynamic investigations with pressure-flow study analysis and flexible urethrocystoscopy.

RESULTS

A significant correlation was found between bladder trabeculation and grade of bladder outlet obstruction. Detrusor instability correlated significantly with grade of trabeculation. Grade of obstruction showed a clear correlation with prostatic occlusion of the urethra and the presence of a middle lobe at cystoscopy.

CONCLUSIONS

The findings at urethrocystoscopy correlate well with those of urodynamic investigations.

Combinations of maximum urinary flow rate and American Urological Association symptom index that are more specific for identifying obstructive and non-obstructive prostatism

Uroflowmetry and the American Urological Association symptom index (AUASI) are often used clinically to evaluate patients with benign prostatic hyperplasia (BPH). Since results from these tests may be used to determine a treatment course, including surgical intervention, we investigated if specific combinations of uroflowmetry and AUASI parameters could better predict urodynamically confirmed prostatic obstruction. Data from 134 men (mean age: 67.8 +/- 8.9 years) with prostatism were analyzed. The patients underwent uroflowmetry in the standing position after completing the AUASI; the post-void residual volume (PVR) was determined. The presence and severity of prostatic obstruction was assessed by video urodynamics, which included micturitional urethral pressure profilometry (MUPP). Of the 134 total patients, 66 were found to be obstructed by MUPP. Correlations of maximum urinary flow rate (Qmax), PVR, and AUASI with the degree of obstruction were poor and not substantially improved using combinations of these parameters. Threshold values of Qmax and AUASI, when used in combination, allowed accurate prediction of obstruction or non-obstruction in a small subset of the patient population. Of 14 men with both Qmax < 10 ml/s and AUASI > or = 20, 13 were obstructed (specificity = 98%). Eight of 9 men with both Qmax > or = 15 ml/s and AUASI < 10 were non-obstructed. The combined Qmax and AUASI criteria categorized only 20% of the patients as obstructed or non-obstructed. Once other causes of urinary dysfunction are ruled out, use of these criteria will enable the urologist to make an accurate diagnosis of obstruction, select a treatment more likely to benefit the patient, and make further diagnostic testing unnecessary in this small subset of patients. In a large volume clinical practice of adult male voiding dysfunctions, diagnosis of even this small proportion of patients using this simple approach can reduce patient care costs.

Laser prostatectomy: initial experience and urodynamic follow-up

OBJECTIVES

An evolving technology for the treatment of bladder outlet obstruction due to benign prostatic hyperplasia (BPH) is the use of the side-firing neodymium: yttrium-aluminum-garnet (Nd:YAG) laser to achieve prostatic tissue ablation. The purpose of this study was to determine the short-term efficacy of this procedure in both an objective and subjective manner.

METHODS

We examined this technique by carefully evaluating our first 25 men undergoing the procedure. Each patient was subjected to careful symptom score analysis using the American Urological Association symptom index and multichannel urodynamics, including pressure-flow studies both preoperatively and at 3 months postoperatively.

RESULTS

At the 3-month follow-up, symptom scores improved from a preoperative mean of 11.4 to 7.2 and the mean maximum flow rate improved from 6.1 to 14.5 cc/s. These are both significant at P < 0.001. Statistically similar improvement was seen in detrusor pressure at opening and at maximum flow. Eighty percent of the men studied had at least a 50% reduction in symptom score and a 50% improvement in flow rate.

CONCLUSIONS

We conclude that laser prostatectomy is a promising minimally invasive treatment for bladder outlet obstruction secondary to BPH and deserves further evaluation at longer terms of follow-up.