UPJ INSIGHT Outcome Measures and Inclusion/Exclusion Criteria in Benign Prostatic Hyperplasia Trials on ClinicalTrials.gov

By: Michael Tram, Albany Medical Center, New York; Jacob Zipkin, MD, SUNY Downstate, Brooklyn, New York; Shreya Srivastava, Albany Medical Center, New York; Charles Welliver, MD, Albany Medical Center, New York, Albany Stratton Veterans Affairs Medical Center, New York | Posted on: 27 Jun 2023

Tram M, Zipkin J, Srivastava S, Welliver C. Outcome measures and inclusion/exclusion criteria in benign prostatic hyperplasia trials on ClinicalTrials.gov. Urol Pract. 2023;10(3):253-260.

Study Need and Importance

Clinical trials are essential to evaluate new treatments for benign prostatic hyperplasia. ClinicalTrials.gov is a public registry that provides access to ongoing and completed studies. Our study investigated benign prostatic hyperplasia trials registered on ClinicalTrials.gov. We were concerned that studies utilized different outcome measures and inclusion criteria, which may limit the ability to both understand trial outcomes and compare results across trials.

What We Found

Out of 411 registered and examined trials, the most common primary or secondary outcome measure was the International Prostate Symptom Score (IPSS), which was used in only 65% of studies (see Figure). Maximum urinary flow (Qmax) was the second most common outcome measure (40% of studies). No other outcome was measured in more than 30% of studies. Inclusion criteria varied between studies, with the most common being a minimum IPSS (49%), maximum Qmax (35%), and minimum prostate volume (26%). The most common minimum IPSS for inclusion was 13 (35% of studies that used IPSS).

Figure. Use of different outcome measures and inclusion criteria. IPPS indicates International Prostate Symptom Score; PVR, post-void residual; Qmax, maximum urinary flow.

Exclusion criteria were often vague (eg, “other chronic medical condition that would make it difficult to participate”), making it difficult to understand the patient population in some studies.


This study examined information on ClinicalTrials.gov, which does not standardize reporting of outcomes or study criteria. Additional details may have been included in the manuscript of published studies that were not reported on the website.

Interpretation for Patient Care

Most trials utilized IPSS as an outcome. However, only 65% used this validated and ubiquitous questionnaire as a primary or secondary outcome. There were significant differences in the inclusion criteria in the examined studies. Exclusion criteria were too often vague, making it difficult to understand the patient population in studies.

Future research should consider using standardized outcome measures (like IPSS and Qmax) when assessing urinary symptoms/function and well-defined inclusion/exclusion criteria.