A 72-year-old man has to get up 3 times per night to urinate. Frequent, nocturnal urination has been a problem for the past several years, but has recently worsened. Despite the sensation that his bladder is full, initiating urination has become more difficult during the last few months and he often has a very weak urine stream. Several episodes of urinary incontinence occurred the week he was evaluated by his physician. He does not have hematuria, dysuria, prior urinary tract infection (UTI), or other history of prostate or urinary tract problems. When evaluating this patient, which lower urinary tract symptoms are most suggestive of bladder outlet obstruction?
Bladder outlet obstruction causes several clinical symptoms including a weak urine stream, a sensation of incomplete urination, and urinary frequency. These symptoms are referred to as lower urinary tract symptoms. Lower urinary tract symptoms include voiding or obstructive symptoms such as hesitancy; poor or intermittent stream, or both; straining; prolonged micturition; dribbling; and storage or irritative symptoms such as frequency, urgency, urge incontinence, and nocturia.1 The most commonly reported lower urinary tract symptoms include urinary hesitancy, weak urine stream, and nocturia.2 Benign prostatic hyperplasia (BPH) frequently causes lower urinary tract symptoms and is very common in men older than 60 years. Among individuals aged 81 to 90 years, the prevalence of BPH approaches 90%.3,4 Benign prostatic hyperplasia is associated with benign smooth muscle and epithelial cell proliferation within the prostate's transition zone.5 The transition zone has 2 lobes and surrounds the proximal urethra (Figure 97-1). The prostate is located at the base of the bladder and contains the prostatic urethra. Cellular hyperplasia expands the transition zone volume, compressing the urethra and resulting in bladder outlet obstruction and subsequent lower urinary tract symptoms. Benign prostatic hyperplasia does not always result in bladder outlet obstruction and patients with BPH may be asymptomatic.
Anatomy and Spatial Relationship of the Prostate Gland to the Lower Urinary Tract
This diagram illustrates the normal spatial relationship of the prostate gland to the bladder, urethra, and rectum. From the bladder neck, the prostatic urethra runs through the entire length of the prostate gland before becoming the membranous urethra where it traverses the external urethral sphincter. These close relationships help to illustrate how enlargement of the transition zone, which surrounds the prostatic urethra, may result in bladder outlet obstruction.
In older men, lower urinary tract symptoms may be caused by many clinical conditions (Box 97-1). Causes of lower urinary tract symptoms other than BPH can be important6 and include structural or functional abnormalities of the lower urinary tract7 (Box 97-1).
Box 97-1. Causes of Lower Urinary Tract Symptoms Other Than Bladder Outlet Obstruction Secondary to Benign Prostatic Hyperplasia
Primary bladder neck obstruction
Bladder neck contracture
Bladder dysfunction (ie, overactive bladder)
Urinary tract infections
Malignancies (ie, bladder cancer, prostate cancer)
Chronic pelvic pain conditions (ie, prostatitis, interstitial cystitis)
Medications (ie, diuretics)
General medical conditions (ie, congestive heart failure)
Nervous system dysfunction
Adapted from Abrams et al,6 2013, and Abrams et al,7 2002.
Prescription drugs such as antidepressants, antihistamines, bronchodilators, anticholinergics, and sympathomimetics can cause or exacerbate lower urinary tract symptoms because of their effects on detrusor muscle and urinary sphincter function. Diuretics increase urine volume and can cause lower urinary tract symptoms.8 An overactive bladder associated with impaired detrusor muscle contractility may by itself or in combination with other diseases cause lower urinary tract symptoms. Bladder overactivity often causes lower urinary tract symptoms in men who were unresponsive to therapy and initially thought to have bladder outlet obstruction.6
Several complications may result if bladder outlet obstruction is untreated, highlighting the need to establish its underlying cause.6,9 These complications include recurrent UTI, bladder stones, overflow incontinence, gross hematuria, hydronephrosis, acute urinary retention, and renal disease.2 Symptoms related to bladder outlet obstruction are detrimental to a patient's quality of life and result in a large number of outpatient visits.2,4,5 In the United States, almost 8 million visits were made in 2000 by patients with a primary or secondary diagnosis of BPH.10 Population-based assessments show that outpatient office visits for bladder outlet obstruction in Canada increased by more than 50% between 2000 and 2004. These increases in outpatient visits place a significant burden on the health care system at large. In the United States, the direct cost of medical services for treatment of BPH provided at hospital inpatient and outpatient settings, emergency departments, and physician offices was estimated to be $1.1 billion in 2000.10
Most patients with lower urinary tract symptoms will first present to their primary care practitioner.2,11 Recognition of risk factors associated with bladder outlet obstruction at initial presentation identifies patients at risk for complications who might benefit from medical treatment (α-blockers, 5-α reductase inhibitors, or both) or specialist referral to avoid complications. The reference standard tests for diagnosing bladder outlet obstruction are invasive pressure-flow studies, which are referred to as urodynamic studies and are performed by urologists.
Urodynamic studies are performed in 2 phases to provide an assessment of the main functions of the bladder, which are urine storage at low pressure (filling phase) and effective voluntary emptying (voiding phase). It involves placement of a small catheter to slowly fill the bladder with normal saline as well as to measure the pressure in the bladder. An intrarectal probe is also placed to measure the intraabdominal pressure. During the voiding phase, external measurement of urinary flow as well as the detrusor pressure (calculated by subtracting the intraabdominal pressure from the intravesical pressure) allows the generation of various indices of bladder outlet resistance (eg, the Abrams-Griffiths nomogram) to make a diagnosis of bladder outlet obstruction. The underlying principle is that detrusor pressure during micturition reflects outlet resistance with the hallmark of bladder outlet obstruction being a high-pressure, low-flow system.12 In the Abrams-Griffiths nomogram, maximal urinary flow while voiding is plotted against the corresponding voiding detrusor pressure to make a determination whether the bladder outlet is obstructed, unobstructed, or equivocally obstructed.
Quantifying the extent of lower urinary tract symptoms provides valuable information on severity of disease, response to therapy, and symptom progression.5,13-15 Although there are many surveys, the most commonly used questionnaire is the American Urological Association Symptom Index, also known as the International Prostate Symptom Score (IPSS).5 The questionnaire was originally designed in 1992 to quantify the intensity of symptoms from BPH.16 It was then adapted by the World Health Organization in 1993 to create the IPSS based on the 7 original questions of the American Urological Association Symptom Index plus 1 question to assess the degree to which patients find their symptoms bothersome, now known as the bother score.17
The IPSS and the American Urological Association Symptom Index are often used interchangeably. In this article, the index will be referred to as the IPSS.
Because the initial presentation of symptoms will probably occur in the office of the nonspecialist or primary care practitioner, it is important to evaluate the diagnostic accuracy of the commonly used screening methods for bladder outlet obstruction. The objective of this systematic review was to determine the diagnostic accuracy of individual symptoms and questionnaires compared with urodynamic studies (the reference standard) for the diagnosis of bladder outlet obstruction in males with lower urinary tract symptoms.
A secondary objective was to determine the correlation of retained urine volumes measured by bladder scanners and those measured by bladder catheterization. Normal bladder function results in emptying to completion with no retained urine volume, or a postvoid residual volume of zero. Therefore, increasing postvoid residual volumes reflect deterioration of emptying function. Although there is currently no standardized definition of a normal postvoid residual urine volume, the widely accepted value is less than 200 mL.18 Large postvoid residual volumes of 200 mL or greater indicate substantially diminished bladder emptying, which is a risk factor for the development of UTIs. Potential long-term complications of worsening bladder emptying include acute renal failure and urinary retention.
Literature Search Strategy
Searches of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (from 1950-March 2014) were completed to identify diagnostic studies of patients with lower urinary tract symptoms due to bladder outlet obstruction. The search strategy used terms, including benign prostatic hyperplasia, lower urinary tract symptoms, and prostatitis, combined with validated search filters for retrieving articles19,20 on the diagnosis of health disorders (Supplemental Appendix). Additional articles were hand searched by reviewing the reference lists of the included original research studies as well as those of review articles and editorials on this topic. In addition, we contacted experts in the field to identify unpublished studies relevant to this topic. A second literature search was conducted to identify studies using a bladder scanner, which is a portable bedside tool, as a measure of urine volume. This second search included MEDLINE, EMBASE, CINAHL, and the Cochrane Library (from 1950-March 2014). The search terms bladder scanner, portable ultrasound, and bladder ultrasound were used (Supplemental Appendix). Appropriate wild cards were used in the search strategy to account for plurals and variations in spelling.
Study Selection and Data Extraction
To identify diagnostic studies for patients with lower urinary tract symptoms due to bladder outlet obstruction, inclusion criteria were chosen to select prospective studies of findings (history, physical examination, simple bedside tests) in adult men conducted in a primary care or other clinical setting. The study populations included inpatients or outpatients with at least 1 type of lower urinary tract symptom. The studies must have included at least 1 diagnostic (or index) test compared with urodynamic studies (the reference standard test). The diagnostic test used in each study had to be readily available to nonspecialist clinicians to be eligible for inclusion. The study must have applied the same diagnostic test to most patients (>90%), applied the same reference tests to all patients, and included participants with and without bladder outlet obstruction. Additionally, primary data or appropriate summary statistics had to be available. When necessary, additional data were obtained by contacting individual study authors. The reference standard was bladder outlet obstruction identified by urodynamic studies. Studies of populations with predominant conditions other than clinically suspected BPH that might cause bladder outlet obstruction, such as a history of recent spinal injury or surgery, neurological disease (such as multiple sclerosis or stroke), urethral stricture disease, or pelvic radiation, were excluded. For the literature search of studies comparing urine volumes measured with a bladder scanner vs bladder catheterization, only prospective studies of adults were included. Studies that included only female patients were excluded. This review was limited to English-language publications.
Two reviewers (K.A.D. and C.L.W.) independently reviewed each title and abstract to select relevant publications for further review. When there was disagreement, the full text was obtained for review and discussion. Two investigators (K.A.D. and C.L.W.) independently reviewed each full-text article to confirm that selection criteria were met. Disagreements were resolved by discussion, and when necessary, with a third reviewer (P.D.).
For the outcome examining diagnostic studies of patients with lower urinary tract symptoms due to bladder outlet obstruction, information was extracted using a specially designed form based on the principles outlined by the Standards for Reporting of Diagnostic Accuracy.21 Risk of bias and applicability concerns were evaluated on eligible studies using the Quality Assessment of Diagnostic Accuracy Studies 2 criteria.22 Extracted details pertaining to study quality included sample size, participant recruitment method, demographic characteristics of participants, application of reference standard, application of at least 1 diagnostic test, presence of blinding, and independent comparison. Study quality was summarized using a quality checklist designed for the Rational Clinical Examination series in which level 1 is the highest quality study and level 5 is the lowest.23
Sensitivity, specificity, likelihood ratios (LRs), and diagnostic odds ratios were calculated from the raw data and then rounded for display in the data tables.24 If a study contained any zeros in the 2 × 2 table (resulting in likelihood estimates of zero or infinity), 0.5 was added to all the counts for that study to enable calculation of the LRs and 95% confidence intervals. If a symptom or sign was evaluated in only 2 studies, sensitivity, specificity, and LRs were expressed by range. When a symptom or sign was evaluated in 3 studies, results were summarized with univariate random-effects measures (Comprehensive MetaAnalysis, version 2.2046, Biostat Inc). The diagnostic odds ratio (positive LR or negative LR) is a single indicator of test performance in which higher values indicate better discriminatory test performance. Heterogeneity for findings evaluated in 3 or more studies was quantified using the I2 index. Heterogeneity was considered low for an I2 value of 25%; moderate, 50%; or high, 75%.25 Publication bias was assessed using a funnel plot and quantified with the test by Begg and Mazumdar.26
Diagnostic Accuracy Study Characteristics
For studies of diagnostic accuracy, we identified 8628 potential citations of which 288 unique studies were retrieved for full-text review. There were 278 studies excluded for a variety of reasons, leaving 10 articles suitable for data extraction and synthesis (Supplemental Figure 1).27,28,29,30,31,32,33,34,35,36 Two publications reported data from the same study population,29,30 therefore these data were examined as 1 study. Overall, 5 studies were rated as having level 3 quality of evidence using the Rational Clinical Examination quality scale,29,30,32,33,34,35 3 studies were rated level 4,27,28 and 1 study was rated level 5 (Supplemental Table 1).31
Supplemental Figure 1.
Flowchart of Study Selection Process: Men with LUTS with Suspected BOO1
Supplemental Table 1.Characteristics of Studies Performed in Men with LUTS with Suspected BOO |Favorite Table|Download (.pdf) Supplemental Table 1. Characteristics of Studies Performed in Men with LUTS with Suspected BOO
|Source ||Study Size ||Prevalence of BOO ||Patient and setting characteristics ||Recruitment Method ||Diagnostic Test(s) ||Reference Standard ||Blinded, Independent Assessment ||Level of Evidence3 ||Comments |
|Aganovic1 2004 ||102 ||64% (65/102) ||Patients with proven benign prostatic enlargement at a university center in Bosnia and Herzegovina ||Not specified. || |
1. IPSS ≥ 8
2. IPSS ≥ 20
|Pressure-flow analysis, defined by combination of URA and Schaffer nomograms (either Schaffer nomogram LinPURR ≥3, or if LinPURR =2 and URA > 28 cm H20) ||Not specified ||4 || |
|Aganovic et al.2 2012 ||200 ||58% (115/200) ||Patients from Urodynamics Unit of Sarajevo University Clinical Center Urology Department with LUTS suggestive of BPE; mean age 64.4 years (49-82) ||Not specified. || |
1. IPSS ≥ 8
2. IPSS ≥ 14
3. IPSS ≥ 20
|Pressure/flow studies were plotted on the Schaefer obstruction class and ICS nomograms; UDS were based on the International Continence Society methodology and terminology ||Not specified ||4 || |
|Ding et al,3 1997 ||126 ||38% (48/126) ||Inpatients or outpatients, age ≥65 years, referred to a continence clinic in Singapore with LUTS after transient causes of incontinence excluded. Excluded patients with TURP, those unable to give a history because of aphasia, or patients who could not be catheterized due to urethral stricture ||Not specified. || |
1. poor stream, frequency and/or nocturia
2. frequency (daytime >8x)
5. urge incontinence
7. poor stream
8. intermittent stream
9. sensation of incomplete emptying
11. manual compression
12. terminal dribbling
|Pressure-flow analysis, defined by the Abrams-Griffiths nomogram >40 or mean slope of plot >2 cm H2O/ml s-1 ||No ||4 || |
|Oelke M,4 (2007) ||160 ||47% (75/160) ||Outpatients aged ≥40 years with clinical BPH, LUTS and/or prostate volume >25 ml referred to a urologic outpatient department of an academic hospital in Germany. Excluded patients with α-blockers, 5-α-reductase inhibitors, urinary retention, prior lower urinary tract or pelvic surgery, evidence prostate carcinoma, or a neurologic deficit. ||consecutive ||IPSS ≥ 14 ||Pressure-flow analysis, defined by the CHESS classification (fields A1, A2, and B1 were considered as non-obstruction and all other fields as obstruction) ||Yes ||3 || |
|Reynard et al,5,6 1996 ||160 ||47% (75/160) ||Outpatients aged ≥40 years with clinical BPH, LUTS and/or prostate volume >25 ml referred to a urologic outpatient department of an academic hospital in Germany. Excluded patients with α-blockers, 5-α-reductase inhibitors, urinary retention, prior LUT or pelvic surgery, evidence prostate carcinoma, or a neurologic deficit. ||consecutive ||IPSS ≥ 14 ||Pressure-flow analysis, defined by the CHESS classification (fields A1, A2, and B1 were considered as non-obstruction and all other fields as obstruction) ||Yes ||3 || |
|Reynard et al,5,6 1996 ||157 ||61% (95/157) ||Patients age ≥ 50, with LUTS suggestive of BOO, referred by general practitioner in the UK. Excluded patients withDM, active UTI, previous LUT surgery (except diagnostic cystoscopy), prostate cancer, or receiving medication active on the LUT. ||consecutive || |
Symptoms of :
1)intermittency, ("Does your urinary stream end with a dribble? Never, occasionally, sometimes, most of the time, all of the time?")
2)terminal dribbling ("Do you stop and start more than once while you urinate? Never, occasionally, sometimes, most of the time, all of the time?")
|Pressure-flow analysis, defined by the Abrams-Griffiths nomogram >40 ||No ||3 ||There were 8 additional patients in the study who did not undergo the diagnostic test and reference test. |
|Sirls et al,7 1996 ||75 ||53% (40/75) ||Patients mean age 67 years (range 42-85) with LUTS suggestive of BOO. Excluded patients with biopsy proven prostate adenocarcinoma. ||Not specified. ||AUA Symptom Index ≥ 20 ||Pressure-flow analysis, defined by the Abrams-Griffiths nomogram ||Not specified ||5 || |
|Steele et al,8 2000 ||204 ||74% (152/204) ||Patients mean age 67 years with LUTS. Excluded patients with previous therapy for voiding dysfunction, positive neurological history, significant co-morbid disease, history of urethral stricture and prostate cancer. ||Not specified. || |
1. AUA Symptom Index ≥ 8
2. AUA Symptom Index ≥ 20
|Pressure-flow analysis, defined by the Abrams-Griffiths nomogram ||No ||3 ||There were an additional 24 patients for which data were incomplete. |
|van Venrooij et al,9 2008 ||160 ||54% (87/160) ||Outpatients with LUTS suggestive of BPH, age ≥ 50 years, who did not have any of specified exclusion criteria of International Consensus Committee on BPH; voided sufficient volume (>150 ml), had reliable pressure-flow relationship, had frequency-volume charts completed for at least 24 hrs, had reliable estimate of PVR, and prostate volume determined by transrectal U/S. ||consecutive || |
1. AUA Symptom Index ≥ 8
2. AUA Symptom Index ≥ 20
|Pressure-flow analysis, defined by the Abrams-Griffiths nomogram> 40 ||Not specified ||3 ||There were an additional 173 patients in a validation study analyzed separately. |
|Yalla et al,10 1995 ||78 ||79% (62/78) ||Patients with symptoms of prostatism referred to VA urology clinic in the USA for urodynamic evaluation. ||consecutivea || |
1. AUA Symptom Index ≥ 8
2. AUA Symptom Index ≥ 20
|Pressure-flow analysis, defined by International Continence Society guidelines. ||Not specified. ||3 ||There were an additional 47 patients in the study with co-morbidities, analyzed separately. |
The included studies ranged in size from 75 to 204 participants (n = 1262; Supplemental Table 1). A variety of symptom combinations with different formats to elicit their presence have been used to qualitatively and quantitatively measure lower urinary tract symptoms (Supplemental Table 2). The IPSS was the most frequently studied index (Box 96-2).
Box 97-2. International Prostate Symptom Score Questionnaire Urinary Symptoms
Incomplete emptying: during the past month, how often have you had a sensation of not emptying your bladder completely after you finish urinating?
Frequency: during the past month, how often have you had to urinate again <2 hours after you finished urinating?
Intermittency: during the past month, how often have you found you stopped and started again several times when you urinated?
Urgency: during the past month, how difficult have you found it to postpone urination?
Weak stream: during the past month, how often have you had a weak urinary stream?
Straining: during the past month, how often have you had to push or strain to begin urination?
Nocturia: during the past month, how many times did you most typically get up to urinate from the time you went to bed until the time you got up in the morning?
Scoring, items 1-6: 0, not at all; 1, <1 time in 5 times; 2, less than half the time; 3, about half the time; 4, more than half the time; 5, almost always.
Scoring, item 7: 0, none; 1, once; 2, twice; 3, 3 times; 4, 4 times; 5, ≥5 times.
Total score: 0-7, mildly symptomatic; 8-19, moderately symptomatic; 20-35, severely symptomatic.
Quality of Life
If you were to spend the rest of your life with your urinary condition the way it is now, how would you feel about that?
Scoring: 0, delighted; 1, pleased; 2, mostly satisfied; 3, mixed (about equally satisfied and dissatisfied); 4, mostly dissatisfied; 5, unhappy; 6, terrible.
Reprinted with permission from Elsevier; published originally by Barry et al,16 1992.
Supplemental Table 2.Diagnostic Accuracy of Questionnaires and Symptoms for Diagnosing BOO |Favorite Table|Download (.pdf) Supplemental Table 2. Diagnostic Accuracy of Questionnaires and Symptoms for Diagnosing BOO
|Source Diagnostic test with threshold ||Sample Size ||Age ||BOO Prevalence, % ||Sensitivity, % (95% CI) ||Specificity, % (95% CI) ||LR+ (95% CI) ||LR− (95% CI) ||Diagnostic Odds Ratio (95% CI) |
|Symptom Questionnaires || |
|IPSS/AUA SI ≥ 20 || |
|Aganovic2, 2012 ||200 ||Mean 64 ||58 (115/200) ||24 (16-32) ||72 (61-81) ||0.83 (0.52-1.3) ||1.1 (0.90-1.3) ||0.78 (0.41-1.5) |
|Steele et al,8 2000 ||204 ||Mean 67 ||74 (152/204) ||46 (38-54) ||67 (53-80) ||1.4 (0.92-2.2) ||0.80 (0.63-1.0) ||1.8 (0.91-3.4) |
|van Venrooij et al,9 2008 ||160 ||Mean 65 ||54 (87/160) ||44 (33-55) ||75 (64-85) ||1.8 (1.1-2.8) ||0.75 (0.60-0.94) ||2.4 (1.2-4.7) |
|Yalla et al,10 1995 ||78 ||Mean 68 ||79 (62/78) ||29 (18-42) ||69 (41-89) ||0.93 (0.41-2.1) ||1.0 (0.72-1.5) ||0.90 (0.27-3.0) |
|IPSS ≥ 14 || |
|Aganovic2, 2012 ||200 ||Mean 64 ||58 (115/200) ||57 (48-66) ||60 (49-71) ||1.4 (1.0-1.9) ||0.73 (0.55-0.95) ||1.9 (1.1-3.5) |
|Oelke et al,4 2007 ||160 ||Median 62 ||47 (75/160) ||69 (58-79) ||41 (31-52) ||1.2 (0.93-1.5) ||0.75 (0.49-1.1) ||1.6 (0.82-3.0) |
|IPSS/AUA SI ≥ 8 || |
|Aganovic 2, 2012 ||200 ||Mean 64 ||58 (115/200) ||98 (94-100) ||19 (11-29) ||1.2 (1.1-1.4) ||0.09 (0.02-0.39) ||13 (2.9-59) |
|Steele et al,8 2000 ||204 ||Mean 67 ||74 (152/204) ||91 (86-95) ||14 (6-26) ||1.1 (0.94-1.2) ||0.64 (0.27-1.5) ||1.7 (0.63-4.43) |
|van Venrooij et al,9 2008 ||160 ||Mean 65 ||54 (87/160) ||97 (90-99) ||12 (6-22) ||1.1 (1.0-1.2) ||0.28 (0.08-1.0) ||3.9 (1.0-15.1) |
|Yalla et al,10 1995 ||78 ||Mean 68 ||79 (62/78) ||86 (74-93) ||0 (0-21) ||0.88 (0.77-1.0) ||5.1 (0.31-84) ||0.17 (0.01-3.09) |
|Symptoms || |
|Poor stream3 ||126 ||Median 75 ||38 (48/126) ||58 (43-72) ||65 (54-76) ||1.7 (1.1-2.5) ||0.64 (0.44-0.92) ||2.6 (1.3-5.5) |
|Nocturia3 ||126 ||Median 75 ||38 (48/126) ||96 (86-100) ||22 (13-33) ||1.2 (1.1-1.4) ||0.19 (0.05-0.79) ||6.4 (1.4-29.1) |
|Frequency (daytime > 8 times)3 ||126 ||Median 75 ||38 (48/126) ||71 (56-83) ||55 (43-66) ||1.6 (1.2-2.1) ||0.53 (0.33-0.86) ||2.9 (1.4-6.4) |
|Intermittent stream || |
|Ding et al,3 1997 ||126 ||Median 75 ||38 (48/126) ||40 (26-55) ||76 (65-85) ||1.6 (0.96-2.8) ||0.80 (0.62-1.0) ||2.0 (0.94-4.4) |
|Reynard et al,6 ||157 ||Median 68 ||60 (95/157) ||23 (15-33) ||82 (71-91) ||1.3 (0.68-2.5) ||0.93 (0.80-1.1) ||1.4 (0.62-3.1) |
|Urge incontinence3 ||126 ||Median 75 ||38 (48/126) ||73 (58-85) ||23 (14-34) ||1.4 (0.60-3.5) ||1.2 (0.63-2.2) ||0.81 (0.35-1.8) |
|Manual compression3 ||126 ||Median 75 ||38 (48/126) ||2 (0-11) ||97 (91-100) ||1.4 (0.83-2.3) ||1.0 (0.95-1.1) ||0.81 (0.07-9.2) |
|Straining3 ||126 ||Median 75 ||38 (48/126) ||17 (8-30) ||89 (79-95) ||1.3 (0.75-2.1) ||0.94 (0.81-1.1) ||1.5 (0.55-4.3) |
|Terminal dribbling || |
|Ding et al,3 1997 ||126 ||Median 75 ||38 (48/126) ||38 (24-53) ||73 (50-62) ||1.4 (0.83-2.3) ||0.86 (0.66-1.1) ||1.6 (0.76-3.5) |
|Reynard et al,5 1996 ||155 ||Median 68 ||61 (94/155) ||50 (40-61) ||57 (44-70) ||1.2 (0.82-1.7) ||0.87 (0.65-1.2) ||1.3 (0.79-2.6) |
|Urgency3 ||Median 75 ||126 ||38 (48/126) ||88 (75-95) ||13 (6-22) ||1.0 (0.88-1.2) ||0.98 (0.38-2.5) ||1.0 (0.35-3.0) |
|Hesitancy3 ||Median 75 ||126 ||38 (48/126) ||44 (28-57) ||69 (58-79) ||0.95 (0.77-1.2) ||0.84 (0.64-1.1) ||1.6 (0.76-3.4) |
|Sensation of incomplete emptying3 ||Median 75 ||126 ||38 (48/126) ||35 (22-51) ||72 (61-81) ||0.81 (0.08-8.7) ||0.90 (0.70-1.2) ||1.4 (0.65-3.0) |
Four studies specified that participant recruitment was consecutive for lower urinary tract symptoms suggestive of bladder outlet obstruction.29,30,33,34,35 The other studies recruited older patients from a continence clinic,28 patients with proven benign prostatic enlargement,27,36 patients with lower urinary tract symptoms,32 and patients with lower urinary tract symptoms suggestive of bladder outlet obstruction.31 Application of the reference test, complete urodynamic studies, and diagnostic tests were similar within each study. In 8 studies, the diagnostic test was applied to 100% of the sample population.27,28,31,32,33,34,35,36 In the other study population examined in 2 reports,29,30 93% to 95% of the participants received the diagnostic tests.
Prevalence of Bladder Outlet Obstruction
From the quality level 3 studies, bladder outlet obstruction occurred in more than half the patients with lower urinary tract symptoms (summary prevalence, 64%; 95% CI, 52%-74%).29,30,32,33,34,35 Considering studies of all quality levels, the highest prevalence, 79%, was in a study (quality level 3) of patients referred to a US Veteran Affairs urology clinic34 and the lowest, 38%, was in a study (quality level 4) of patients referred to a continence clinic in Singapore (Supplemental Table 1).28
Accuracy of Symptoms in the Diagnosis of Bladder Outlet Obstruction
Table 97-2 displays the summary data for diagnostic accuracy of questionnaires and symptoms for diagnosing bladder outlet obstruction from the highest quality studies (all quality level 3). The studies examined a variety of lower urinary tract symptoms, including the presence of poor urine stream, nocturia, frequency, intermittent stream, urge incontinence, manual compression, straining, terminal dribbling, urgency, hesitancy, and sensation of incomplete emptying (Supplemental Table 2) with respect to diagnosing bladder outlet obstruction. Among these, only the presence of an intermittent stream or terminal dribbling were evaluated in level 3 studies and both had LRs with 95% CIs that included 1.0. In the studies of lesser quality among patients referred for evaluation of incontinence, the complaint of a poor stream increased the likelihood of bladder outlet obstruction (positive LR, 1.7; 95% CI, 1.1-2.5), whereas the absence of nocturia (negative LR, 0.19; 95% CI, 0.05-0.79) made bladder outlet obstruction less likely (Table 97-2).28
Table 97-2.Summary Data for Diagnostic Accuracy of Questionnaires and Symptoms for Diagnosing Bladder Outlet Obstruction From Level 3 Studiesa |Favorite Table|Download (.pdf) Table 97-2. Summary Data for Diagnostic Accuracy of Questionnaires and Symptoms for Diagnosing Bladder Outlet Obstruction From Level 3 Studiesa
|Diagnostic Test by Threshold ||Sample Size ||Age, y ||Bladder Outlet Obstruction Prevalence, No./Total (%) ||Sensitivity (95% CI), % ||Specificity (95% CI), % ||Positive LR (95% CI)b ||Negative LR (95% CI)b ||Diagnostic OR (95% CI) |
|IPSS/AUA Symptom Index ≥20 || || || || || || || || |
| Steele et al,32 2000 ||204 ||Mean, 67 ||152/204 (74) ||46 (38-54) ||67 (53-80) ||1.40 (0.92-2.20) ||0.80 (0.63-1.00) ||1.80 (0.91-3.40) |
| van Venrooij et al,33 2008 ||160 ||Mean, 65 ||87/160 (54) ||44 (33-55) ||75 (64-85) ||1.8 (1.1-2.8) ||0.75 (0.60-0.94) ||2.4 (1.2-4.7) |
| Yalla et al,34 1995 ||78 ||Mean, 68 ||62/78 (79) ||29 (18-42) ||69 (41-89) ||0.93 (0.41-2.10) ||1.00 (0.72-1.50) ||0.90 (0.27-3.00) |
| Summary || || || ||41 (30-52) ||71 (63-78) ||1.5 (1.1-2.0); I2 = 75% ||0.82 (0.67-1.00); I2 = 6.4% ||1.8 (1.2-2.8) |
|IPSS ≥14 || || || || || || || || |
| Oelke et al,35 2007 ||160 ||Median, 62 ||75/160 (47) ||69 (58-79) ||41 (31-52) ||1.20 (0.93-1.50) ||0.75 (0.49-1.10) ||1.60 (0.82-3.00) |
|IPSS/AUA Symptom Index ≥8 || || || || || || || || |
| Steele et al,32 2000 ||204 ||Mean, 67 ||152/204 (74) ||91 (86-95) ||14 (6-26) ||1.10 (0.94-1.20) ||0.64 (0.27-1.50) ||1.70 (0.63-4.43) |
| van Venrooij et al,33 2008 ||160 ||Mean, 65 ||54 (87/160) ||97 (90-99) ||12 (6-22) ||1.1 (1.0-1.2) ||0.28 (0.08-1.00) ||3.9 (1.0-15.1) |
| Yalla et al,34 1995 ||78 ||Mean, 68 ||62/78 (79) ||86 (74-93) ||0 (0-21) ||0.88 (0.77-1.00) ||5.10 (0.31-84.00) ||0.17 (0.01-3.09) |
| Summary || || || ||91 (85-95) ||12 (8-19) ||1.00 (0.89-1.10); I2 = 75% ||0.58 (0.28-1.20); I2 = 44% ||1.60 (0.49-5.40) |
|Intermittent stream29 ||157 ||Median, 68 ||95/157 (60) ||23 (15-33) ||82 (71-91) ||1.30 (0.68-2.50) ||0.93 (0.80-1.10) ||1.40 (0.62-3.10) |
|Terminal dribbling29 ||155 ||Median, 68 ||94/155 (61) ||50 (40-61) ||57 (44-70) ||1.20 (0.82-1.70) ||0.87 (0.65-1.20) ||1.30 (0.79-2.60) |
The IPSS was studied most frequently in the highest quality studies at thresholds of 20 or greater (severe symptoms) and 8 or greater (moderate symptoms) to determine if the results predict bladder outlet obstruction (Table 97-2). The positive LR for bladder outlet obstruction might have increased slightly from lower to higher thresholds, but even at a greater severity with an IPSS of 20 or greater, the positive LR was only 1.5 (95% CI, 1.1-2.0). Likewise, the ability of the IPSS to rule out bladder outlet obstruction improved as the symptoms decreased. However, even at the lowest threshold (IPSS <8), the negative LR was only 0.58 (95% CI, 0.28-1.20). Thus, the IPSS results did not have much effect on the probability of bladder outlet obstruction beyond the baseline prevalence among patients with lower urinary tract symptoms and therefore were of limited clinical utility.
Accuracy of Physical Examination for the Diagnosis of Bladder Outlet Obstruction
Many studies included the use of the digital rectal examination but none had data on its diagnostic accuracy. There were no studies that met our inclusion criteria in which the rectal examination for prostate enlargement or bladder percussion was compared with a reference standard for bladder outlet obstruction.
Accuracy of Bladder Scanner for Assessment of Urine Volume
We identified 2254 citations that compared assessment of urine volume by bladder scan with bladder catheterization, of which 57 unique studies were retrieved for full-text review and 20 studies37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56 met the inclusion criteria (Supplemental Figure 2). The included studies varied in sample size from 15 to 186 (Supplemental Table 3). In the 14 studies38,39,40,41,42,44,45,47-50,53,54,56 that specified the range of urine volumes measured with bladder catheterization, the range was 0 to 1269 mL. Fourteen studies37,39,40,42,43,44,45,46,49,51,52,53,54,56 examined the correlation between urine volumes measured with a bladder scanner and postvoid residual volumes, and 8 studies38,41,47,48,49,50,53,55 examined the correlation between urine volumes measured with a bladder scanner and prevoid urine volumes. The patient populations were varied, containing both men and women, and being conducted in inpatient and outpatient, and acute care and rehabilitation settings (Supplemental Table 3). The summary correlation coefficient was r = 0.93 (95% CI, 0.91-0.95). This suggests that the urine volumes measured with a bladder scanner and those measured with bladder catheterization were highly correlated. There was heterogeneity (I2 = 88%), but no evidence of publication bias (Begg and Mazumdar rank correlation, P = .36).
Supplemental Figure 2.
Flowchart of Study Selection Process: Reliability of Bladder Scanner as a Measure of Urine Volume2
Supplemental Table 3.Study Characteristics for Bladder Scan Correlation with Catheterized Urine Volumes |Favorite Table|Download (.pdf) Supplemental Table 3. Study Characteristics for Bladder Scan Correlation with Catheterized Urine Volumes
|Study ||U/S Instrument ||Study Group ||Gender ||Recruitment ||Catheterized Bladder Volume (mL) ||Number of Measurements ||Number of Staff Using Ultrasound ||Reference Standard ||Correlation Coefficient (95% CI) ||Other Indices of Agreement |
|Araki et al,11 2003 (N=15) ||BVI 3000 ||Post-resection rectal cancer patients with midline wound incisions ||mixed ||not specified ||not specified ||15 ||not specified ||post-void residual catherization ||r=0.90 (0.72-0.97) || |
|Barrington et al,12 1996 (N=75; 25 post-clam enterocytoplasty, 50 control) ||BVI 2500 ||post clam enterocytoplasty ||mixed ||not specified ||range (40-790) ||≥ 3 erect and supine in clam enterocytoplasty group, not specified in control group ||2 ||catheterization || |
r = 0.96 (0.94-0.98) post-clam enterocytoplasty;
r = 0.98 (0.96-0.99) controls
|Borrie et al,13 2001 (N=19) ||BVI 2500+ ||Geriatric rehabilitation unit, only patients with bladder scan ≥ 150 rnl on two consecutive ||mixed ||not specified ||mean (434.1), range (10-900) ||1 pre-void, and 1 post void residual per patient ||not specified ||post-void residual catheterization ||r = 0.87 (0.69-0.95) ||Scan volumes underestimated catheterization volumes by an average of 80.6± 111.3 ml; mean absolute error was 101.2 ml, which is 74.1% |
|Cardenas et al,14 1988 (N = 15) ||BVI 2000 ||inpatient rehabilitation, spinal cord injury ||mixed ||not specified ||mean (262.5), range (2-1269) ||224 total measurements, ~4 per catheterization; 57 catheterizations ||2 ||post-void residual catheterization ||catheterized volume versus average u/s volume r = 0.89 (0.82-93) ||mean difference between catheterized volume and average u/s volume = 56 mL ±99.8 (n=57) |
|Chan,15 1993 (N=41) ||MK100 ||stroke unit ||mixed ||consecutive ||range (0-710) ||70 paired measurements ||not specified ||catheterization ||r=0.98 (0.97-0.99) ||Ultrasound measurements were −70 to +60 mL different from catheterized volumes |
|Choe et al,16 2007 (N=99) ||BME-150A ,BVI 3000 ||urology clinic prior to UDS for LUTS ||mixed ||not specified ||mean (117.2), range (0-78) ||116 paired measurements on 99 patients ||2 ||post-void residual catheterization || |
r=0.92 (0.89-0.94), BVI 3000
Mean difference between catheterized volume and BME-150A volume =7.8 ml
Mean difference between the catheterized volume and BVI 3000 volume = 3.6 ml
|Coombes and Millard,17 1994 (N=100; Group 1=50, Group 2=50)) ||Group 1 BVI 2500, Group 2 BVI 2500+ ||undergoing video urodynamic studies ||mixed ||not specified ||Group 1 mean (100); Group 2 mean (110) ||100, 1 per catheterization ||1 ||post-void residual catheterization || |
Group 1: r=0.86 (0.77-0.92);
Group 2: r=0.97 (0.95-0.98)
Group 1: mean difference from the true residual volume = 41 ml. (95% CI 26 to 55 ml)
Group 2: mean difference from the true residual volume = 24 ml. (95% CI 17 to 31 ml)
|Ding et al,18 1996 (N=46) ||BVI 2500 ||geriatrics patients: inpatient or outpatient attending continence clinic ||mixed ||not specified ||Range (5-1150) ||100 paired measurements ||1 (blinded to u/s results) ||post-void residual catheterization ||r=0.96 (0.94-0.98) ||Mean absolute error of BVI 25000 = 52 ml |
|Fuse et al,19 1996 (N=110) ||BVI 2000 ||72 with BPH, 38 with neurogenic bladder ||mixed ||not specified ||mean (124), range (2-530) ||130 paired measurements ||not specified ||post-void residual catheterization ||r=0.98 (0.97-0.99) ||Mean BVI 2000 error: 22% |
|Ireton et al,20 1990 (N=112) ||BVI 2000 ||urology clinic, cystoscopy clinic and spinal cord injury patients ||mixed ||not specified ||not specified ||656 total measurements, ~4 per catheterization; 164 paired measurements ||2 ||residual urine by cystoscopy or catheter ||r=0.89 (0.85-0.92) || |
|Marks et al,21 1997 (N=182; BVI 2500=81, BVI 2500+=101) ||BVI 2500, BVI 2500+ ||urology outpatients ||mixed ||not specified ||Range (0-1015) ||556 total measurements, ~3 per catheterization; 182 paired measurements ||5 (blinded) ||catheterization ||BVI 2500 r=0.96; BVI 2500+ r=0.96 ||Mean ultrasound error: −15 ml |
|Massagli et al,22 1989 (N=16) ||BVI 2000 ||inpatient, neurogenic bladder ||mixed ||not specified ||Supine range (7-500); Seated range (2-500) ||31 pairs of experienced seated; 31 pairs of learner seated; 32 pairs of experienced supine; 32 pairs of learner supine ||2 ||catheterization || |
experienced seated r=0.90 (0.80-0.95);
experienced supine r=0.88 (0.77-0.94); learner seated r=0.92 (0.84-0.96); learner supine r=0.89 (0.79-0.95)
Mean difference true-ultrasound experienced: −14mL
|O'Farrell et al,23 2001 (N=21) ||BVI 5000 ||Acute neuroscience unit ||mixed ||not specified ||mean (550), range (150-1250) ||67 paired measurements ||34 ||38 catheterized pre-void; 28 post-void residual; 1 unclear whether pre- or post-void ||average of first and second readings r=0.86, (0.78-0.91) ||First ultrasound volume readings underestimated catheterized volumes M=550ml, with mean absolute error of 105 ml (22%); |
|Oh-Oka and Fujisawa,24 2007 (N=160) ||BVI 6100 ||urology clinic ||mixed ||not specified ||Range (0-150) ||3 per catheterization ||not specified ||catheterization ||r = 0.94 (0.92-0.96) || |
|Ouslander et al.,25 1994 (N=186) ||BVI 2000, BVI 2500 ||incontinent, nursing home residents ||mixed ||consecutive ||not specified ||744, 4 per catheterization ||2 of research nurse, associate and physician ||post-void residual catheterization || ||PVR <50 mL sensitivity 0.90, specificity 0.71; <100 mL sensitivity 0.95, specificity 0.63; >200 mL sensitivity 0.69, specificity 0.99 |
|Revord et al,26 1993 (N=24) ||BVI 2000 ||inpatient rehabilitation unit, neurogenic bladder ||male ||not specified ||not specified ||400, 4 per catheterization; 100 paired measurements ||2 ||post-void residual catheterization || ||mean error of ultrasonographic measurement was −26 mL (−11%); residual urine volume ≥100mL, Sensitivity 90%, Specificity 81%; residual urine volume ≤200 mL, Sensitivity 77%, Specificity 81% |
|Schott-Baer and Reaume,27 2001 (N=48) ||BVI 2500 ||general surgery and rehabilitation inpatients ||mixed ||not specified ||men mean (489), range (140-900); women mean (493.7), range (75-800) ||1 per catheterization ||unclear ||Catheter or post-void residual ||r=0.94 (0.90-0.97)1 || |
The mean difference score was 79 (SD=68.5) with 50% of the volumes underestimated. 12 patients had difference scores of ≤20. 10% of patients had differences scores ≥100
Difference score = actual volume – scan volume
|Teng et al,28 2005 (N=71) ||BVI 3000 ||inpatients and outpatients attending rehabilitation hospital ||mixed ||not specified ||mean (188.6), range (25-900) ||142, 2 per catheterization || ||post-void residual catheterization || ||mean urine volume was measured sitting on bladder scan = 189.9; mean urine volume was measured supine on bladder scan = 188; mean catheterization volume = 188.6; (F=0.50, p=.61, repeated-measures ANOVA) |
|Topper et al,29 1993 (N=36) ||BVI 2000 ||geriatricscontinence clinic, urology clinic ||mixed ||not specified ||Not specified ||64 measurements total each by nurse and physician ||2 (nurse and physician) ||catheterization ||nurse r=0.89 (0.83-0.93); physician r=0.80 (0.69-0.87) || |
|Yucel et al,30 2005 (N=21; 11 hemodialysis, 10 peritoneal dialysis) ||BVI 3000 ||End stage renal disease patients, candidates for renal transplant ( ||male ||not specified || |
HD mean (21.36) range (0-120);
PD mean (15.4) range (0-110)
|63(3 per catheterization) ||2 (physician, technician) ||post-void residual catheterization ||Hemodialysis, physician r=0.921; peritoneal dialysis, physician r=0.055; hemodialysis, technician r=0.904; peritoneal dialysis, technician r=0.336 || |
|OVERALL || || || || || || || || ||0.93 (0.91-0.95) || |
Diagnostic accuracy studies frequently had a high risk of bias related to patient selection.21 The level 4 studies27,28,36 lacked an independent comparison of signs and symptoms with a reference standard for patient selection and had narrowly defined patient populations (Supplemental Table 4). In 4 of the 5 level 3 studies, consecutive sampling was used but these studies did not clearly define the spectrum of disease, range, and relative frequency of alternative conditions in the patient populations without bladder obstruction (Supplemental Table 4).
Supplemental Table 4.Risk of Bias and Applicability Concerns Assessment, QUADAS-2 Tool Results Summary: Studies of Men with LUTS with Suspected BOO |Favorite Table|Download (.pdf) Supplemental Table 4. Risk of Bias and Applicability Concerns Assessment, QUADAS-2 Tool Results Summary: Studies of Men with LUTS with Suspected BOO
|Study ||Risk of Bias ||Applicability Concerns |
|Patient Selection ||Index Test ||Reference Standard ||Flow and Timing ||Patient Selection ||Index Test ||Reference Standard ||Level of Evidence4 |
|Aganovic1 2004 ||high ||Low ||Low ||low ||high ||low ||Low ||4 |
|Aganovic et al.2 2012 ||high ||low ||low ||low ||high ||low ||low ||4 |
|Ding et al,31997 ||high ||Low ||Low ||low ||high ||low ||Low ||4 |
|Oelke et al,4 2007 ||high ||Low ||Low ||low ||low ||low ||Low ||3 |
|Reynard et al,5,6 1996 ||high ||Low ||Low ||high ||low ||low ||Low ||3 |
|Sirls et al,7 1996 ||unclear ||Low ||Low ||low ||low ||low ||Low ||5 |
|Steele et al,8 2000 ||high ||Low ||Low ||high ||low ||low ||Low ||3 |
|van Venrooij et al,9 2008 ||Low ||Low ||Low ||low ||low ||low ||Low ||3 |
|Yalla et al,10 1995 ||Low ||Low ||Low ||low ||low ||low ||Low ||3 |
This review was further limited by the small number of studies fitting the selection criteria and the small sample sizes of the studies. Most of the reviewed studies lacked a blinded, independent assessment of urodynamic studies (Supplemental Table 1).
The main limitation of the bladder scanner assessment was reliance on the correlation coefficient between bladder scanning and catheterization, although only 5 of 22 studies reported differences between urine volumes measured with bladder catheterization and those measured with a bladder scanner. Those that did are summarized in Supplemental Table 3. All of these studies used the means, rather than the medians, as the measure to express the central tendency for measured differences. Means are susceptible to outlying values and can overstate discrepancy.
In the study by Schott-Baer and Reaume,53 the mean difference score (ie, actual urine volume minus scan volume) was 79 mL. Fifty percent of the urine volumes were underestimated by the bladder scanner. In the group of patients that had lower actual urine volumes (range, 200-800 mL), 25% (or 12 patients) had difference scores of 20 mL or less. In the group of patients with larger actual urine volumes (range, 375-900 mL), 10% of patients had difference scores greater than 100 mL. Cardenas et al40 found that the mean of the differences between urine volumes was 56 mL. When actual urine volumes of greater than 500 mL were excluded, the mean difference was reduced to 37 mL. Considering only small actual urine volumes of 200 mL or less, the mean difference was 25 mL.
The bladder scanner was found to underestimate the actual urine volumes. In the study by Massagli et al,48 actual urine volumes ranged from 2 mL to 500 mL and mean differences were about 14 mL for "experienced" personnel. Coombes and Millard43 looked at 2 different types of scanners in their study. The mean difference in urine volume for the 2-step BVI 2500 unit was 41 mL. Over- and underestimations of bladder volume were found in 50% of patients. For the 1-step BVI 2500+, the mean difference in urine volume was 24 mL. In this group, the bladder scanner tended to slightly underestimate actual urine volumes.
Choe et al42 also examined 2 different scanning devices. The mean difference in bladder urine volume for the BME-150A unit was 7.8 mL and with the BVI 3000 it was 3.6 mL. Notably, in plotting the mean differences according to range of actual urine volume, the greatest mean difference was seen in the group with the largest actual volumes (>400 mL). In this study, there were 6 cases in which postvoid residual volume measurements had overestimated actual urine volumes. These patients were later diagnosed with various pelvic pathologies, including ovarian hemorrhagic cyst and uterine myoma.
The results from these studies indicate that larger urine volumes are more vulnerable to discrepancies in measurement. However, discrepancies are usually not clinically relevant because the purpose of measuring residual volumes is simply to recognize whether there is significant urine retention. The techniques of both bladder scanning and catheterization for measuring residual urine volume can be limited in the presence of structural pathology. When there is a high index of suspicion that actual urine volumes are nearing diagnostic thresholds, it would be prudent to do serial bladder scanning to avoid misclassification from the measurement itself but also from daily variations in urinary events.
The low positive LR associated with questionnaires and symptoms implies that these are not useful for diagnosing bladder outlet obstruction. Lower urinary tract symptoms in men are usually attributed to benign prostatic hypertrophy causing bladder outlet obstruction. Questionnaires may fail to identify the correct diagnosis for bladder outlet obstruction because they may lack specificity for identifying other causes for lower urinary tract symptoms, including drugs,8 nervous system, renal, cardiovascular, and respiratory disease or dysfunction.6
The precision of the IPSS as a tool is limited by potentially inaccurate patient recall of symptoms and willingness to report urinary symptoms, which may depend on education, cognitive abilities, and cross-cultural differences in perception.57,58 A patient's symptoms may fluctuate because of comorbid illness, medication use, and hydration status. These may influence the accurate categorization of disease severity depending on the timing of questionnaire administration.59 The IPSS as a tool may reliably measure treatment response once a diagnosis has been established.
Even though guidelines from urological associations recommend the initial evaluation of males with lower urinary tract symptoms to include a digital rectal examination and prostate-specific antigen measurement,5 based on the present review, evidence is lacking for both of these tests as markers for bladder outlet obstruction. The utility of these diagnostic tests for other conditions was beyond the scope of this study.
Lower urinary tract symptoms are very common and nonspecific in aging men. In this 72-year-old patient, the pretest probability of bladder outlet obstruction is 64% based on the studies in this review. His IPSS was 21 (bladder emptying = 4, frequency = 2, intermittency = 2, urgency = 2, weak stream = 5, strain = 3, nocturia = 3) and was obtained to quantify the intensity of his symptoms. A complete medical history, a physical examination with digital rectal examination, and a focused examination to assess for other causes of voiding dysfunction including infection, medication use, other systemic disease, or underlying malignancy did not reveal any positive findings. Using an IPSS of 20 or greater, a positive LR of 1.5 could be applied, resulting in a 73% posttest probability of bladder outlet obstruction.
The IPSS quantifies the symptom intensity and the amount of bother experienced by the patient. A bladder scan performed postvoid revealed 350 mL of urine indicated inefficient bladder emptying as a risk factor for UTIs, which indicates the development of hydronephrosis, acute renal disease, and urinary retention. Catheterization was unnecessary because of the known high correlation with bladder scan results. The patient was referred to a urologist who initiated a trial of an α-blocker and a 5-α reductase inhibitor. Only mild improvement in symptoms resulted. Recent clinical practice guidelines recommend that urodynamic studies confirm bladder outlet obstruction prior to proceeding with invasive ablative therapies such as transurethral resection of the prostate.60 Therefore, urodynamic studies were performed to confirm bladder outlet obstruction. After a thorough discussion about the expected benefits, risks, complications, and alternative approaches such as laser ablation, the patient underwent an uncomplicated transurethral resection of the prostate. A follow-up visit 3 months later revealed a subjectively much improved urinary stream and sensation of bladder emptying. The IPSS was 8.
Among men with lower urinary tract symptoms, the IPSS quantifies the symptoms experienced by the patient along with a measure for the bother caused by the symptoms. However, each lower urinary tract symptom and the IPSS have poor diagnostic accuracy for bladder outlet obstruction. Given that the prevalence of bladder outlet obstruction is high among older men with lower urinary tract symptoms, a bladder scan provides a noninvasive and reliable approach to determine whether the patient has substantial postvoid residual volumes, thereby making it unnecessary for bladder catheterization in the patient as well as providing a useful tool for serial examinations to assess changes in urine volume suggestive of worsening disease.
The following disclosures were reported at the time this original article was first published in JAMA.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Wong reported receiving other from Li Ka Shing Knowledge Institute during the conduct of the study and outside the submitted work. No other disclosures were reported.
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