Urinary urgency: a review of its assessment as the key symptom of the overactive bladder syndrome

Overactive bladder (OAB) is a common condition that is associated with a negative impact on quality of life. Urgency is the essential symptom when making a diagnosis, and its effective treatment is a principal aim in OAB management. However, urgency has often been relatively neglected as an outcome measure in clinical trials. The aim of this review is, first, to describe the background to urgency in OAB; second, to determine whether results provided by several tools used to measure urgency in clinical trials could be cross-related to each other in a meaningful way. The wording of various tools used to measure urgency in OAB was compared against the definition of urgency proposed by the International Continence Society (ICS). Urgency data were evaluated from two randomised, double-blinded, placebo-controlled trials with solifenacin in which seven tools were used to measure urgency as a primary or secondary outcome. In particular, subanalyses were available from these tools, which measured urgency equating to the ICS definition, excluding data points that could be interpreted as normal/strong desire to void. Baseline scores for ICS-defined urgency differed between the tools, which might reflect imprecision in their wording and consequent overlap between urgency and normal/strong desire to void. All the tools detected broadly similar mean percentage reductions in the number of urgency episodes from baseline to the endpoint of the studies. Urgency should be the primary or co-primary endpoint for future studies of OAB and detrusor overactivity. Greater clarity is needed in the development of instruments for measuring urgency, so that they do not confuse urgency with normal bladder sensations; more education and guidance are needed on how urgency is defined.