Urinary incontinence assessment is an essential component of follow-up after radical prostatectomy. The preferred method for this assessment has been the subject of some debate. This study compares the assessment of urinary incontinence using the ICIQ-SF questionnaire with the number of pads used in in a 24 hour period in men 12 months following radical prostatectomy.

Materials and methods: A retrospective analysis of consecutive patients undergoing RP surgery for clinically localised or for locally advanced prostate cancer was undertaken. Patients were excluded if they were undergoing salvage RP or had previously underwent radiation therapy. Continence status was assessed at 12 months following surgery using the Spanish version of the ICIQ-SF and the number of pads used in 24 hours. McNemars test was used to determine if the number of men defined as continent differed between the ‘no pad’ and ICIQ-SF = 0 definitions of continence. Spearman rank-correlation was used to measure the strength of the relationship between the number of pads used and the ICIQ-SF scores. Jonckhere-Terpstra analysis of variance was used to determine whether the ICIQ-SF scores increased with increasing levels of pad usage (0,1 2, 3 or more pads/day).  Pairwise Wilcoxon rank-sum tests with Bonferroni correction were used to determine whether the ICIQ-SF scores were different between the number of pads used to assess the relationship between categorical variables. Wilcoxon rank-sum tests were used to test for differences between two groups. R version 3.4.3 statistical software and a 5% significance level was used for all analysis.

A total of 746 patients were included in the analysis. The continence rate was 82.3% using the ‘no pad’ definition of continence versus 78.0% using the zero ICIQ-SF score definition of continence (p<0.001). A strong positive (Spearman) correlation (0.865, p<0.001) was observed between the ICIQ-SF score and the number of pads used. A Jonckheere-Terpstra test indicated that the ICIQ-SF scores increased significantly (P<0.001) between increasing levels of pad usage.  Pairwise Wilcoxon rank sum tests indicated that the ICIQ-SF scored differed significantly between all pairs of pad use levels (p<0.018). The mean (SD) bother score for men who were incontinent using Q3 of the ICIQ-SF was 4.5 (2.2). A strong (Spearman) positive correlation (0.853, p<0.001) was observed between the ICIQ-SF bother score and the number of pads used.

Results suggest that although the proportion of patients determined to be continent is significantly higher with the no pad use definition of continence, the number of pads used in 24 hours is a good proxy for continence with the pads usage levels (0, 1, 2 and 3 or more) relating to significantly different and increasing ICIQ-SF scores.

Pad use is an easy to collect, clinically relevant indicator of the presence or absence of continence in men 12 months after RP.