Assessment of bladder pressure and discomfort symptoms: How do overactive bladder differ from interstitial cystitis/bladder pain syndrome patients?

Background: To better understand the sensation of bladder “pressure” and “discomfort”, and how they are similar or distinct from the “pain” and “urgency” symptoms in IC/BPS and OAB. Methods: IC/BPS and OAB patients rated their bladder pain, pressure, discomfort, and urinary urgency on separate 0–10 numeric rating scales (NRS). Their NRS ratings were compared between IC/BPS and OAB, and Pearson correlations were performed. Results: Among IC/BPS patients (n = 27), their mean numeric ratings of pain, pressure, discomfort, and urinary urgency were almost identical (6.6 ± 2.1, 6.0 ± 2.5, 6.5 ± 2.2, and 6.0 ± 2.8 respectively). The three-way correlations between pain, pressure, or discomfort were very strong (all > 0.77). Among OAB patients (n = 51), their mean numeric ratings of pain, pressure, and discomfort (2.0 ± 2.6, 3.4 ± 2.9, 3.4 ± 2.9) were significantly lower than urgency (6.1 ± 2.6, p < 0.001). The correlations between urgency and pain, and between urgency and pressure were weak in OAB (0.21 and 0.26). The correlation between urgency and discomfort was moderate in OAB (0.45). The most bothersome symptom of IC/BPS was bladder/pubic pain, while the most bothersome symptom of OAB was urinary urgency and daytime frequency. Conclusions: IC/BPS patients interpreted bladder pain, pressure, or discomfort as the similar concepts and rated their intensity similarly. It is unclear whether pressure or discomfort provide additional information beyond pain in IC/BPS. Discomfort may also be confused with urgency in OAB. We should re-examine the descriptors pressure or discomfort in the IC/BPS case definition.