OAB and IC/BPS: Two Conditions or a Continuum of One?

Purpose of Review Overactive bladder (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS) are defined as syndromes consisting of "urinary urgency, usually accompanied by frequency and nocturia, with or without urgency urinary incontinence" and "an unpleasant sensation perceived to be related to the urinary bladder, associated with lower urinary tract symptoms," respectively. Distinguishing between the two diagnoses can be challenging and although OAB and IC/BPS are traditionally considered separate conditions, more evidence is emerging to suggest a continuum between the symptoms. This review considers the two conditions existing on a continuum by reviewing relevant definitions, phenotypes, and treatment considerations. Recent Findings Recent studies have suggested that up to 25% of patients with IC/BPS reported urge incontinence and 35% of patients with OAB described bladder pain. Analysis assessing validated questionnaires revealed that scores could distinguish controls from patients with storage LUTS but were not able to distinguish between those with OAB and IC/BPS. A novel scoring system spanning domain of urgency incontinence and bladder pain was validated and provided 91% diagnostic accuracy. OAB and IC/BPS symptoms overlap significantly and it remains unclear if patients with IC/BPS and OAB are unique populations or specific phenotypes of the same condition. We propose that "OAB-dry" patients without fear of leakage may represent a variant of IC/BPS. Unbiased phenotyping based on more accurate symptomatic descriptions may help reveal the correlations of variants of lower urinary tract symptoms with both prognosis and treatment responses.