Sensitivity of 1-Hour Pad Test to Change in Time of Incontinence Status after Prostatectomy


Hypothesis/Aims of Study: Pad testing is a simple, non-invasive, and effective method to quantify the amount of urine loss in patients with urinary incontinence. The short-term tests are easy, quick, and provide immediate information. The pad weight result can serve as an excellent and objective outcome procedure before and after treatment in patients with urinary incontinence. It is important, in this case, for the capacity of a test to be responsive to change in an appropriate way after a change of medical conditions There are few studies in literature that assess the sensitivity of 1-hour pad tests to change incontinence status. The post-prostatectomy incontinence model is ideal for this purpose. In fact, the majority of patients recover urinary control after 1 year from surgery, for a natural recovery of rhabdosphincter function. The aim of this study is to assess the validity and reliability of the 1-hour pad test to detect the changes of post-prostatectomy incontinence and its correlation with the number of episodes of urinary leakage and the results of a validated questionnaire.

Study Design, Materials, and Methods: This prospective study was conducted between January 2005 and March 2006, and 102 patients who underwent standard RRP were considered for this protocol after Ethical Committee approval and signed informed consent. All patients were invited to complete an Incontinence Quality of Life (I-QoL) questionnaire, a bladder diary for 1 week to assess the number of incontinence episode frequency (IEF), and an ICS standard 1-hour pad test at 4, 16, and 24 weeks after catheter removal. Incontinence was measured by the number of pads used daily; we defined continence as the use of 0 pads. A positive pad weight result was defined as more than 1 g of leakage. Validity was assessed by calculating the Spearmans’ rank correlation coefficient between the 1-hour pad test, IEF, and I-Qol score. This test was used because the hypothesis of normality was rejected. The responsiveness of the 1-hour pad test to change was assessed by correlating the percentage change in the pad test with the percentage change in I-Qol score and in IEF (chi-square test for difference in proportions).

Results: After 4 weeks, 22 (21.5%) patients were completely dry. After 16 and 24 weeks, complete continence was achieved by 66 (64.7%) and 72 (70.5%) patients, respectively. The 1-hour pad test correlated well with the IEF (Spearman coefficient of rank correlation [rho] = 0.450, P < 0.0001, 95% confidence interval for rho = 0.280 to 0.592), and correlated significantly but much less strongly with I-Qol score (Spearman coefficient of rank correlation [rho] = -0.360, P = 0.0003, 95% confidence interval for rho = -0.518 to -0.178). The change in 1-hour pad test after improving incontinence status correlated well with the improvement in the IEF and I-Qol (Spearman correlation coefficient). At 4 weeks, 17 (16,6%) patients had 0-1 g of urine loss in the pad test; at 16 and 24 weeks, 61 (59,8%) and 68 (66,6%) patients, respectively, lost 0-1 gr of urine in the pad. The difference in the proportions is not statistically significant (95% CI = -5.86 to 15.66; chi-square = 0.508; DF = 1; P = 0.4760).

Conclusion: This study demonstrated how the 1-hour pad test is sensitive to change based on improvement of continence status after radical prostatectomy.