Sensation kinetics identifies novel bladder sensation-capacity curve shapes during urodynamics in patients with urinary urgency

Objective: Overactive bladder (OAB) is characterized by urinary urgency. To better characterize the relationship between bladder sensation and urgency, a tablet-based “Sensation Meter” was developed to enable construction of bladder sensation-capacity curves. The objective of this study was to correlate sensation-capacity curve shapes during urodynamics (UDS) with urgency severity and bother. Methods: Individuals with moderate-to-severe urgency presenting for clinically indicated UDS were prospectively enrolled after urgency characterization using the International Consultation on Incontinence OAB questionnaire (ICIq-OAB). Throughout UDS filling, participants recorded sensation of bladder fullness (0–100 %) using the Sensation Meter. Sensation-capacity curves were constructed and area-under-the-curve (AUC) analysis was implemented to differentiate between three curve-shape patterns defined as r, l, and j-shape. Curve shapes were correlated categorically to urgency severity and bother, UDS capacity, and the presence/absence of DO. Findings: The study included 69 participants (52F, 17M). The distribution of sensation-capacity curve shapes was 7 (10 %) r-shape, 43 (62 %) l-shape, and 19 (28 %) j-shape. A j-shaped curve was significantly associated with severe urgency and with high urgency bother, but not with bladder capacity or DO. Conclusions: The key finding was the association between a j-shaped sensation-capacity curve, demonstrating a rapid acceleration of sensation near the end of filling, with both urgency symptom severity and bother. Curve shapes were not associated with bladder capacity or DO, suggesting that a j-shaped curve may potentially identify a separate driver of urinary urgency. Additional studies are needed to determine whether sensation-capacity curves can be used to identify novel OAB/urgency phenotypes or guide therapy.