Urethral StrictureURINCT07403786
Urethral Resistive Index (URI): A New Parameter for Diagnosing Urethral Obstruction
An observational study of Urethral Stricture, run by Ankara City Hospital Bilkent at 1 site in Turkey (Türkiye).
Trial summary
This prospective observational study aims to evaluate the diagnostic accuracy of a new, non-invasive uroflowmetry parameter called the Urethral Resistive Index (URI) for detecting urethral stricture in men. Read more about this study
- Who is it for?
- Ages 18 to 80 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Urethral Stricture
- What is being tested?
- Uroflowmetry with URI Calculation
- How many people
- 60 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 10 Feb 2026to 10 Jul 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- Men only
- Healthy volunteers accepted
- Adult, Older adult
Study population: The study population consists of 60 male participants, aged 18 to 80 years, recruited from the Urology Outpatient Clinic at Ankara Bilkent City Hospital. The population is divided into two distinct groups: a Stricture Group (n=30) comprising patients with suspected urethral stricture whose diagnosis is confirmed intraoperatively during scheduled surgery, and a Control Group (n=30) comprising healthy male volunteers with a similar age distribution and no lower urinary tract symptoms. Participants are selected based on their clinical presentation and willingness to undergo a specialized two-stage uroflowmetry protocol.
Who may be able to join
- Male participants aged between 18 and 80 years.
- For the Stricture Group: Patients scheduled for surgery (urethroplasty or internal urethrotomy) due to suspected urethral stricture, where the diagnosis is confirmed intraoperatively.
- For the Control Group: Healthy male volunteers without any lower urinary tract symptoms.
- Voluntary signing of the Informed Consent Form.
Who cannot join
- Voiding volume less than 150 mL.
- Causes of obstruction other than stricture, such as Benign Prostatic Hyperplasia (BPH).
- Diagnosis of neurogenic bladder dysfunction or a history of neurological disease affecting bladder function.
- Presence of severe comorbidities.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Ankara Bilkent City Hospital
Ankara, Universiteler, 06800
Yusuf Gökkurt, MD, +90 506 791 0557, yusufgokkurt@gmail.com
About this study
Official title: Urethral Resistive Index (URI): A New Uroflowmetric Parameter in the Non-Invasive Diagnosis of Urethral Obstruction
This prospective observational study aims to evaluate the diagnostic accuracy of a new, non-invasive uroflowmetry parameter called the Urethral Resistive Index (URI) for detecting urethral stricture in men. Currently, diagnosing urethral stricture often requires invasive procedures like surgery or pressure-flow studies. This research seeks to develop URI as a practical and painless screening tool that could reduce the need for such invasive interventions.
Study Procedures:
Read more
A total of 60 male participants (30 with suspected urethral stricture and 30 healthy volunteers) will be enrolled. Participants will undergo two standard, non-invasive uroflowmetry (voiding) tests. The first test is a routine natural voiding session. The second test involves a "forced voiding" (Valsalva maneuver) once the participant feels a sufficient urge to urinate again. The URI is then calculated by comparing the flow rates of these two sessions.
Goals and Benefits: The primary goal is to determine the optimal "cut-off" value of the URI that accurately identifies a surgically proven urethral stricture. By demonstrating URI's effectiveness, the study aims to expedite the diagnostic process and spare patients from unnecessary invasive tests. The procedure involves minimal risk, primarily temporary discomfort or psychological stress during the voiding tests
Read the detailed description
This methodological study is designed as a prospective, cross-sectional, and observational diagnostic accuracy study. The primary objective is to evaluate the clinical validity of the Urethral Resistive Index (URI), a novel non-invasive parameter, in the diagnosis of urethral stricture.
Study Population and Groups:
The study will include a total of 60 male participants aged between 18 and 80 years.
Stricture Group (n=30): Patients planned for surgery (urethroplasty or internal urethrotomy) due to suspected urethral stricture, where the presence of the stricture is confirmed intraoperatively.
Control Group (n=30): Healthy male volunteers without lower urinary tract symptoms, matched for age.
Methodology: The study focuses on comparing standard uroflowmetry with "forced" uroflowmetry using the Valsalva maneuver. All clinical and uroflowmetric parameters will be collected at the Ankara Bilkent City Hospital Urology Clinic.
Natural Uroflowmetry: Participants will perform a standard uroflowmetry test. Forced Uroflowmetry: After reaching sufficient bladder fullness again, participants will perform a second test using the Valsalva maneuver (forced voiding).
Calculation: The URI will be calculated using the formula:
URI= Qmax,forced/ Qmax,normal
Statistical Analysis: The diagnostic performance of the URI will be evaluated using Receiver Operating Characteristic (ROC) curve analysis. The Area Under the Curve (AUC) will be calculated, and the optimal cut-off value for determining urethral stricture will be identified with corresponding sensitivity and specificity values. Correlation between URI and clinical symptom scores, such as the International Prostate Symptom Score (IPSS), will also be analyzed.
- Conditions
- Urethral Stricture
- Being tested
- Uroflowmetry with URI Calculation
- Medical subject headings
- Urethral Stricture
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Uroflowmetry with URI CalculationDiagnostic test
Performing natural and forced (Valsalva) uroflowmetry sessions to calculate the Urethral Resistive Index.
| Study group | Role | What they receive |
|---|---|---|
| Stricture Group | Patients with suspected urethral stricture scheduled for surgery (urethroplasty or internal urethrotomy), with the diagnosis confirmed intraoperatively. Receives: Diagnostic Test: Uroflowmetry with URI Calculation | |
| Control Group | Healthy male volunteers in a similar age range as the stricture group, without any lower urinary tract symptoms. Receives: Diagnostic Test: Uroflowmetry with URI Calculation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Urethral Resistive Index (URI)
A novel non-invasive uroflowmetric parameter calculated to assess the resistance of the urethra during voiding. It is derived using the formula: URI=Qmax,natural/Qmax,forced.
Measured: At the time of the uroflowmetry procedure (Baseline)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Feb 2026
- Study start10 Feb 2026
- Primary completion10 May 2026 (estimated)
- Study completion10 Jul 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Urethral StrictureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ankara City Hospital Bilkent
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Yusuf Gökkurt, Ankara City Hospital Bilkent
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07403786
- Sponsor's protocol ID
- TABED 1/2090/2026
- Acronym
- URI
- Status last verified
- Mar 2026
- First submitted
- 5 Feb 2026
- Last updated
- 6 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: To protect participant privacy and maintain data confidentiality according to local institutional regulations
Publications
Kranse R, van Mastrigt R. Bladder outlet resistance. J Urol. 2003 Mar;169(3):1007-10. doi: 10.1097/01.ju.0000052693.58772.23.
PubMed 12576832Spyropoulos E, Galanakis I, Deligiannis D, Spyropoulou A, Kotsiris D, Panagopoulos A, Mavrikos S. Flow resistive forces index (QRF): Development and clinical applicability assessment of a novel measure of bladder outlet resistance, aiming to enhance the diagnostic performance of uroflowmetry. Low Urin Tract Symptoms. 2020 Sep;12(3):190-197. doi: 10.1111/luts.12301. Epub 2020 Jan 30.
PubMed 31999073Krukowski J, Kaluzny A, Klacz J, Piatkowska A, Matuszewski M. Evaluation of non-invasive tests as diagnostic tools in assessment of bladder outlet obstruction severity in men with anterior urethral stricture. Cent European J Urol. 2021;74(3):422-428. doi: 10.5173/ceju.2021.3.153.R1. Epub 2021 Jul 27.
PubMed 34729232
Study at a glance
From the registry record, last updated by the sponsor on 6 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Urethral Resistive Index (URI): A New Uroflowmetric Parameter in the Non-Invasive Diagnosis of Urethral Obstruction
- ClinicalTrials.gov ID
- NCT07403786
- Acronym / sponsor ID
- URI / TABED 1/2090/2026
- Conditions
- Urethral Stricture
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Ankara City Hospital BilkentUniversity, hospital or other
- Study start
- 10 Feb 2026 (actual)
- Primary completion
- 10 May 2026 (estimated)
- Study completion
- 10 Jul 2026 (estimated)
- First posted
- 11 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This prospective observational study aims to evaluate the diagnostic accuracy of a new, non-invasive uroflowmetry parameter called the Urethral Resistive Index (URI) for detecting urethral stricture in men. Currently, diagnosing urethral stricture often requires invasive procedures like surgery or pressure-flow studies. This research seeks to develop URI as a practical and painless screening tool that could reduce the need for such invasive interventions.
Study Procedures:
A total of 60 male participants (30 with suspected urethral stricture and 30 healthy volunteers) will be enrolled. Participants will undergo two standard, non-invasive uroflowmetry (voiding) tests. The first test is a routine natural voiding session. The second test involves a "forced voiding" (Valsalva maneuver) once the participant feels a sufficient urge to urinate again. The URI is then calculated by comparing the flow rates of these two sessions.
Goals and Benefits: The primary goal is to determine the optimal "cut-off" value of the URI that accurately identifies a surgically proven urethral stricture. By demonstrating URI's effectiveness, the study aims to expedite the diagnostic process and spare patients from unnecessary invasive tests. The procedure involves minimal risk, primarily temporary discomfort or psychological stress during the voiding tests
Detailed description
This methodological study is designed as a prospective, cross-sectional, and observational diagnostic accuracy study. The primary objective is to evaluate the clinical validity of the Urethral Resistive Index (URI), a novel non-invasive parameter, in the diagnosis of urethral stricture.
Study Population and Groups:
The study will include a total of 60 male participants aged between 18 and 80 years.
Stricture Group (n=30): Patients planned for surgery (urethroplasty or internal urethrotomy) due to suspected urethral stricture, where the presence of the stricture is confirmed intraoperatively.
Control Group (n=30): Healthy male volunteers without lower urinary tract symptoms, matched for age.
Methodology: The study focuses on comparing standard uroflowmetry with "forced" uroflowmetry using the Valsalva maneuver. All clinical and uroflowmetric parameters will be collected at the Ankara Bilkent City Hospital Urology Clinic.
Natural Uroflowmetry: Participants will perform a standard uroflowmetry test. Forced Uroflowmetry: After reaching sufficient bladder fullness again, participants will perform a second test using the Valsalva maneuver (forced voiding).
Calculation: The URI will be calculated using the formula:
URI= Qmax,forced/ Qmax,normal
Statistical Analysis: The diagnostic performance of the URI will be evaluated using Receiver Operating Characteristic (ROC) curve analysis. The Area Under the Curve (AUC) will be calculated, and the optimal cut-off value for determining urethral stricture will be identified with corresponding sensitivity and specificity values. Correlation between URI and clinical symptom scores, such as the International Prostate Symptom Score (IPSS), will also be analyzed.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Stricture Group | – | Diagnostic Test: Uroflowmetry with URI CalculationPatients with suspected urethral stricture scheduled for surgery (urethroplasty or internal urethrotomy), with the diagnosis confirmed intraoperatively. |
| Control Group | – | Diagnostic Test: Uroflowmetry with URI CalculationHealthy male volunteers in a similar age range as the stricture group, without any lower urinary tract symptoms. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- The study population consists of 60 male participants, aged 18 to 80 years, recruited from the Urology Outpatient Clinic at Ankara Bilkent City Hospital. The population is divided into two distinct groups: a Stricture Group (n=30) comprising patients with suspected urethral stricture whose diagnosis is confirmed intraoperatively during scheduled surgery, and a Control Group (n=30) comprising healthy male volunteers with a similar age distribution and no lower urinary tract symptoms. Participants are selected based on their clinical presentation and willingness to undergo a specialized two-stage uroflowmetry protocol.
Key inclusion criteria (4 listed)
- Male participants aged between 18 and 80 years.
- For the Stricture Group: Patients scheduled for surgery (urethroplasty or internal urethrotomy) due to suspected urethral stricture, where the diagnosis is confirmed intraoperatively.
- For the Control Group: Healthy male volunteers without any lower urinary tract symptoms.
- Voluntary signing of the Informed Consent Form.
Key exclusion criteria (4 listed)
- Voiding volume less than 150 mL.
- Causes of obstruction other than stricture, such as Benign Prostatic Hyperplasia (BPH).
- Diagnosis of neurogenic bladder dysfunction or a history of neurological disease affecting bladder function.
- Presence of severe comorbidities.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Uroflowmetry with URI CalculationPerforming natural and forced (Valsalva) uroflowmetry sessions to calculate the Urethral Resistive Index. | Diagnostic test | Control Group, Stricture Group |
Primary outcome
Urethral Resistive Index (URI)
Time frame: At the time of the uroflowmetry procedure (Baseline)
A novel non-invasive uroflowmetric parameter calculated to assess the resistance of the urethra during voiding. It is derived using the formula: URI=Qmax,natural/Qmax,forced.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Apr 2026.
- Background: PubMed 12576832Kranse R, van Mastrigt R. Bladder outlet resistance. J Urol. 2003 Mar;169(3):1007-10. doi: 10.1097/01.ju.0000052693.58772.23.
- Background: PubMed 31999073Spyropoulos E, Galanakis I, Deligiannis D, Spyropoulou A, Kotsiris D, Panagopoulos A, Mavrikos S. Flow resistive forces index (QRF): Development and clinical applicability assessment of a novel measure of bladder outlet resistance, aiming to enhance the diagnostic performance of uroflowmetry. Low Urin Tract Symptoms. 2020 Sep;12(3):190-197. doi: 10.1111/luts.12301. Epub 2020 Jan 30.
- Background: PubMed 34729232Krukowski J, Kaluzny A, Klacz J, Piatkowska A, Matuszewski M. Evaluation of non-invasive tests as diagnostic tools in assessment of bladder outlet obstruction severity in men with anterior urethral stricture. Cent European J Urol. 2021;74(3):422-428. doi: 10.5173/ceju.2021.3.153.R1. Epub 2021 Jul 27.
- Individual participant dataSharing planned: No. To protect participant privacy and maintain data confidentiality according to local institutional regulations
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Urethral Stricture, run by Ankara City Hospital Bilkent at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 6 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Yusuf Gökkurt (+90-506-791-0557, yusufgokkurt@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Urethral Resistive Index (URI) (time frame: At the time of the uroflowmetry procedure (Baseline)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07403786, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Apr 2026.