Bladder sensation in health and disease

Determining bladder sensation pattern in healthy people is challenging, as there is sparse evidence on how individuals perceive it. A rapid, non-invasive water-load protocol had been developed and used previously to assess bladder sensation but the reliability remained unproven. In this study I validated the protocol and then examined the pattern of bladder sensation in healthy volunteers before comparing this with patients with different lower urinary-tract symptoms (LUTS). A test-retest analysis in twelve healthy volunteers showed no difference in median volume of first void (p=0.43). A fixed diuresis rate was achieved (12.1ml/min [8.9- 17.2]). Although no difference was found in the diuresis rate when drinking 250ml/15min (n=7) and 300ml/15min (n=5), the variation was reduced when drinking 300ml (3.03 ml/min [1.55-4.54]). A second validation test was done using 300ml/15min only, and confirmed the previous results. I identified the upper 95% confidence interval of diuresis rate variation as 4.5ml/min. The final protocol was validated as drinking 300ml/15min and using a cut off for exclusion by variation in diuresis rate between cycles of more than 4.5 ml/min. In a confirmatory validation study, 21 volunteers completed the final protocol. After excluding those with diuresis rate variation over the threshold there were 16 participants for analysis. Median voids or diuresis rates within or between tests were not different. Area under the curve (AUC) was calculated from bladder sensation curves and was reproducible: median 404.96 [247.28-557.14] in test 1 vs 418.63 [262.50- 596.02] in test 2 (p=0.234). These data provided proof of concept that AUC is a valid analysis. Finally, 74 patients with different LUTS were compared. Bladder sensation patterns were exactly the same in all groups when comparing AUC (p=0.853). This thesis validated a bladder sensation protocol, and demonstrated that bladder sensation develops identically in volunteers and patients with different LUTS and conditions.