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Objectives: To investigate whether volume adjustment can be used to reduce the within-patient variability of the maximal urinary flow rate (Qmax) without affecting the variability between patients., Methods: We analyzed 2049 urinary flow curves of 208 men with lower urinary tract symptoms suggestive of bladder outlet obstruction and studied the relation between Qmax and voided volume (VV) in individual patients using multilevel regression analysis., Results: In agreement with most previous studies, we found a hyperbolic relation between the VV and Qmax. Although hyperbolic on average, the slope of the regression line relating the VV to Qmax differed substantially across individual patients. In some patients, Qmax even tended to be lower with an increased VV., Conclusions: The reproducibility of Qmax is poor, in part because of its dependence on the VV. The current methods to adjust Qmax for VV, such as the Siroky nomogram, minimize between-patient dependency, whereas our findings emphasize the importance of within-patient variability. A common approach to adjust Qmax for VV, however, is not feasible, because the relation of Qmax to VV differs substantially across patients. The only valid, although impractical option, remains to record a large number of urinary flow curves for each patient.

Objectives: To evaluate the relative accuracy of a computerised method to quantitatively assess maximum urinary flow., Methods: A total of 1147 uroflows were evaluated by the computerised method and by three experts from different European countries. The sample consisted of uroflows from the respective visits by a 20% sample of randomly chosen patients (n = 223) with lower urinary tract symptoms with participation in two clinical trials in which the efficacy and safety of Permixon was evaluated. The proportions of automated maximum flow values included in the 10% extended range of experts (and their 95% confidence intervals) were assessed, as well as the concordance coefficients between experts and the computerised method and the paired Student's t-test for the average differences between experts and computer., Results: The rate of agreement between experts and computer varied between about 95 and 100% over factor levels for visit, type of machine and country. Concordance coefficients indicated good agreement between experts and the automated method. When looking at average differences between experts and the computer, the smallest differences were observed between experts 2, 3 and the computer (differences not statistically significant). Statistically significant average differences were observed between expert 1 and the other experts as well as between expert 1 and the computer., Conclusions: The computerised assessment decreases the fraction of variability of maximum urinary flow caused by artifacts as well as intra- and inter-expert variation. The computerised assessment of maximum urinary flow is an efficient, consistent and valid approach to quantitatively assess maximum urinary flow in clinical trials.

Objectives: To evaluate a computerized method of artifact detection and correction of uroflow and compare the quantitative assessment of maximum flow obtained by the computer with visual correction by experts., Methods: A total of 90 randomly chosen flows was scanned into the computer whereafter automated artifact detection and correction was performed according to pre-established rules implemented in the software. Three experts visually corrected the flows using the same artifact detection and correction specifications as the computer. Measuring agreement between different methods of assessment of maximum flow was evaluated by calculating the difference and the standard deviation (SD) of the differences. The repeatability of assessing the maximum flow value by the computer and by expert 1 was assessed by calculating the difference between 2 readings and the coefficient of repeatability., Results: The coefficient of repeatability of maximum flow after detection and correction of artifacts by the computer (0.38 ml/s) was slightly better when compared with the coefficient of repeatability between 2 observations by 1 expert (1.12 ml/s). The interobserver variation for the quantitative assessment of maximum flow appeared to be great. A total of 51% of the maximum flow values assessed by expert 2 was 1 ml/s or more greater than those assessed by expert 1. When comparing the results of the computer with those of the experts, the mean value of maximum flow from expert 1 was 0.71 ml/s smaller than the computer value (p < 0.01), the mean value from expert 2 was 0.53 ml/s greater (p < 0.01) and the mean value from expert 3 was not significantly different (0.25 ml/s greater). The SD of maximum flow after correction by the computer was 0.3 ml/s smaller than the SD of the raw data from the flowmeter and the corrected values by 2 experts., Conclusions: Computerized artifact detection and correction eliminates an important fraction of the variability of manually corrected maximum flow values. This may lead to smaller sample size requirements, especially in studies where the primary objective is to assess a small (+/- 1 ml/s) difference in mean maximum flow between groups.

Objectives: To investigate if the circadian rhythm of urinary flow values varies within groups of patients with varying degrees of bladder outlet obstruction., Methods: A total of 170 patients with lower urinary tract symptoms suggestive of bladder outlet obstruction used a home-based uroflowmeter and produced a total of 1670 correctly measured flows at home. These patients also underwent a screening program with free urinary flowmetry in the hospital and a urodynamic pressure and flow study., Results: There is a circadian variability in urinary flow values in men with higher grades of obstruction. These men have a higher peak urinary flow with a smaller voided volume and thus a shorter flow time in the early afternoon when compared with late evening, early morning, and the midnight to morning periods., Conclusions: This significantly greater maximum flow in the afternoon in men with higher grades of obstruction can be an important bias in studies where the primary end point is to assess a small improvement in maximum flow. Therefore, the circadian rhythm of uroflow has to be taken into account in the evaluation of the efficacy of treatment. Patients participating in clinical research studies should produce their urinary flow in the clinic always during the same time period, either in the morning or in the afternoon, and should not switch their appointment time.

Objective: To determine if, in patients with lower urinary tract symptoms (LUTS), measurement of the transition zone (TZ) of the prostate by transrectal ultrasonography (TRUS) and the ratio between the TZ volume and total prostate volume (TZ index) correlates better with clinical and urodynamic investigations than total prostate volume alone., Patients and Methods: In total, 150 consecutive patients with LUTS underwent a standardized screening programme including the International Prostate Symptom Sore (IPSS), a physical examination, TRUS of the prostate and urodynamic investigations with pressure-flow studies. The total prostate volume and TZ volume were assessed from TRUS using the ellipsoid formula. Spearman's rank correlation coefficients were calculated between different prostate volume measurements and specific symptomatic and urodynamic variables., Results: The relationships between specific IPSS symptoms, symptom scores and the prostate volume measurements were not statistically significant except for one domain, nocturia, that appeared to be statistically significantly correlated with the TZ index (r = 0.25). The correlations for free flow, pressure-flow variables and prostate volume measurements were stronger, but only moderate at best. The highest correlations were between TZ volume and the linear passive urethral resistance obstruction category, urethral resistance factor and detrusor pressure at maximum flow (r = 0.43, 0.44 and 0.40, respectively). The differences between the correlations of prostate volume and TZ index and these variables were small (r = 0.39, 0.38 and 0.37, respectively for prostate volume and r = 0.38, 0.40 and 0.33 respectively for TZ index)., Conclusions: There were very small differences between the correlations of total prostate volume, TZ volume and TZ index, and clinical and pressure-flow variables. In the assessment of the last two, the estimation of the total prostate volume by TRUS was a reasonable way to obtain the required information about prostate size and measuring TZ volume and calculating TZ index was of limited additional value. Symptoms and bladder outlet obstruction were mainly determined by other factors than the prostate and, specifically, TZ volume. As earlier studies have indicated that including pressure-flow data in the pre-operative evaluation and selection of patients for interventional therapies may improve the overall clinical results, we think that prostate volume, TZ volume or symptoms alone should not be used as the main indication for deciding on the appropriate invasive treatment options.

Objectives: We investigated the symptomatic and urodynamic effects of several noninvasive and minimally invasive treatment modalities to quantify these effects and to compare subjective and objective results within groups with various degrees of obstruction., Methods: In a prospective study at one center, 487 patients who completed a full screening program including urodynamic investigation started treatment with watchful waiting, terazosin, transurethral microwave thermotherapy, or laser treatment of the prostate; they were re-evaluated symptomatically and urodynamically after 6 months of therapy. The symptomatic and urodynamic results of 87 patients from another center who underwent transurethral resection of the prostate and who had their second urodynamic evaluation 6 months after surgery were also included., Results: In patients without bladder outlet obstruction (BOO), improvement in maximum flow and symptom scores with little change in the degree of obstruction was most apparent, whereas a decrease of detrusor pressure at maximum flow was observed mainly in patients with BOO. The urodynamic effect but not the symptomatic effect of treatments depended on the initial grade of BOO. Urodynamic changes were more marked in the minimally invasive treatment groups compared with the noninvasive treatment groups., Conclusions: In symptomatic patients with benign prostatic hyperplasia, symptomatic improvement in the short term does not seem to depend on changes in urodynamic parameters. Future well-controlled studies focusing on the durability of symptomatic and urodynamic effects will be needed to illustrate the relative potential of urodynamic and other clinical parameters to predict a favorable response to current and innovative treatments.

Purpose: We quantified the physiological variability of clinical and pressure-flow study variables in patients with symptomatic benign prostatic enlargement., Materials and Methods: Symptom scores were measured, and advanced urodynamic studies with pressure-flow analysis were performed in 178 patients before and 6 months after a period a watchful waiting., Results: Patients without bladder outlet obstruction experienced significant symptomatic improvement. Symptoms in patients with obvious bladder outlet obstruction did not improve significantly. The reproducibility of mean pressure-flow variables was evident. However, there was an important intra-individual variability. Patients with obvious bladder outlet obstruction showed a significant decreases in detrusor pressure at maximal flow of 14cm. water, a significant decrease in the urethral resistance factor of 7 cm. water and a significant decrease of 1 obstruction class on the linear passive urethral resistance relation nomogram, indicating less severe bladder outlet obstruction., Conclusions: Mean differences among therapy groups must be regarded critically, especially when the difference are slight and possibly within physiological variability.

Objectives: To compare the results obtained using a portable home-based uroflowmeter with the results of traditional flowmetry performed in the out-patient department (OPD)., Patients and Methods: Sixty-seven patients (mean age 61 years, range 38-79) with lower urinary tract symptoms and/or benign prostatic enlargement used a home-based uroflowmeter comprising a datalogger and specially designed fluid sensors incorporated into disposable beakers. The results of these measurements were compared with those from uroflowmetry in the OPD and with other clinical variables., Results: There was a good correlation between the uroflow results obtained when voiding at home and at the OPD. The highest measured maximum flow and voided volume were obtained with the home-based uroflowmeter system. However, the mean of all consecutive home-based maximum flow and voided volume measurements were lower than those obtained by single-void uroflowmetry in the OPD., Conclusions: Home-based uroflowmetry provides reliable voiding results which are comparable with those obtained in the OPD.

Purpose: We evaluated the urodynamic and clinical effects of terazosin in patients with symptomatic benign prostatic hyperplasia (BPH)., Materials and Methods: A total of 45 patients who participated in a multicenter trial was evaluated with urodynamic pressure-flow studies before and after 26 weeks of treatment., Results: Maximum flow rate and symptom score improved significantly in 22 patients with and 11 without bladder outlet obstruction who completed 26 weeks of treatment. In patients with bladder outlet obstruction the condition was significantly reduced and in patients without obstruction, significant urodynamic changes could not be detected., Conclusions: Terazosin treatment results in symptomatic relief and improved urinary flow in patients with and without bladder outlet obstruction, and in significant improvement in patients with urodynamically proved obstruction.