Systematic Review of the Performance of Noninvasive Tests in Diagnosing Bladder Outlet Obstruction in Men with Lower Urinary Tract Symptoms

Context:
Several non-invasive tests have been developed for the diagnosis of bladder outlet obstruction
(BOO) in men to avoid the burden and morbidity associated with invasive urodynamics. The
diagnostic accuracy of these tests, however, remain uncertain.
Objective:
To systematically review the available evidence regarding the diagnostic accuracy of noninvasive
tests in diagnosing BOO in men with lower urinary tract symptoms (LUTS) using
the pressure-flow study as a reference standard.
Evidence acquisition:
The EMBASE, MEDLINE, Cochrane Database of Systematic Reviews, Cochrane Central, Google
Scholar, and WHO International Clinical Trials Registry Platform Search Portal databases were
searched up to May 18th 2016. All studies reporting the diagnostic accuracy of non-invasive tests for
BOO or DUA in men with LUTS compared to pressure-flow studies were included. Two reviewers
independently screened all articles, searched the reference lists of retrieved articles, and performed the
data extraction. The quality of evidence and risk of bias was assessed using the QUADAS-2 tool.
Evidence synthesis:
The search yielded 2,774 potentially relevant reports. After screening titles and abstracts 53 reports
were retrieved for full-text screening, of which 42 (recruiting a total of 4444 patients) proved eligible.
Overall, the results were predominantly based on findings from non-randomised experimental studies
and, within the limits of such study designs, the quality of evidence was typically moderate across the
literature. Differences in the non-invasive test BOO threshold values and variations in the urodynamic
definition of BOO between studies limited the comparability of the data. The detrusor wall thickness
(median sensitivity 82%, specificity 92%), near-infrared spectroscopy (median sensitivity 85%,
specificity 87%), and penile cuff test (median sensitivity 88%, specificity 75%) were all found to have
high sensitivity and specificity in diagnosing BOO. Uroflowmetry with a maximum flow rate of less
than 10ml/s was reported to have a lower median sensitivity and specificity of 68% and 70%,
respectively. Intravesical prostatic protrusion of more than 10mm was reported to have a similar
diagnostic accuracy with a median sensitivity and specificity of 68% and 75%.
Conclusions:
A number of non-invasive tests have been shown to have a high sensitivity and specificity in the
diagnosis of BOO in men. However, although the majority of studies have a low overall risk of bias
the available evidence is limited by heterogeneity. While several tests have shown promising results
regarding the non-invasive assessment of BOO, invasive urodynamics remain the gold standard.
Patient summary:
Urodynamics is an accurate but potentially uncomfortable test for patients in diagnosing bladder
problems such as obstruction. We performed a thorough and comprehensive review of the literature to
determine if there were less uncomfortable but equally effective alternatives to urodynamics for
diagnosing bladder problems. We found some simple tests which appear promising although they
were not as accurate. Further research is needed before these tests are routinely used in place of
urodynamics