Symptomatic Overlap in Overactive Bladder and Interstitial Cystitis/Painful Bladder Syndrome - development of a new algorithm

To address challenges in the diagnosis and classification of storage Lower Urinary Tract Symptoms (LUTS), we sought to define the fundamental features of overactive bladder (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS), two conditions with considerable symptomatic overlap. Through retrospective comparison of self-reported symptoms in women with a range of clinical presentations and symptom severities, we have attempted to refine OAB and IC/BPS diagnostic features and develop a novel clinical nomogram to improve patient screening and classification.

We performed a univariate analysis comparing responses to the female Genitourinary Pain Index (fGUPI), OAB Questionnaire (OAB-q) and O'Leary-Sant Indices (ICSI/ICPI) enrolling an initial cohort of 50 OAB & IC/BPS patients and control subjects. Only eight questions differed significantly between the IC/BPS and OAB groups; we used five unique questions and three measuring bother to generate a novel composite scoring system and nomogram with urgency incontinence, bladder pain, and symptomatic bother domains to differentiate these populations, which was validated in a second cohort of 150 subjects. Addition of a self-reported bother index resulted in the creation of a diagnostic algorithm to identify and classify LUTS clusters across the total population.

While all validated questionnaires could distinguish between controls and storage LUTS, no combined symptom scores differed significantly between the IC/BPS and OAB patients. These results are reflective of the prevalence of significant bladder pain (35%) in OAB patients and the presence of urge incontinence (25%) in IC/BPS patients. Only the fGUPI Pain Domain differed between OAB and IC/BPS patients, but it was not accurate enough for diagnostic evaluation (68% accuracy). Our composite scores and nomogram gave a much-improved diagnostic accuracy (94%) and demonstrated utility as a screening tool to identify storage LUTS in patients presenting for unrelated complaints, e.g. microhematuria.

There is significant overlap of urinary tract symptoms between OAB and IC/BPS. We present a novel algorithm that provides a binary output capable of guiding clinical diagnosis. Future studies aimed at assessing the diagnostic value of novel classification schemes that address symptoms rather than specific diagnoses may improve patient prognosis. This article is protected by copyright. All rights reserved.

BJU international. 2018 Sep 25 [Epub ahead of print]

A Lenore Ackerman, H Henry Lai, Pooja S Parameshwar, Karyn S Eilber, Jennifer T Anger

Department of Surgery, Division of Urology, Cedars-Sinai Medical Center, Los Angeles, CA., Departments of Surgery (Urology) and Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri.