The 24-h pad test in the assessment of post-prostatectomy incontinence: is there still a role for counting pads per day?

Abstract

To evaluate the correlation between the pad-per-day (PPD) count and the 24-h pad test (24 h-PT) during the first postoperative year after radical prostatectomy (RP), and to determine the clinical utility of the PPD count for quantitative urinary incontinence (UI) assessment. We retrospectively analysed a prospectively maintained database of 2040 men who underwent RP between 2001 and 2025 at a tertiary referral centre. A total of 8787 paired measurements of PPD count and 24 h-PT were analysed. Urinary leakage was assessed at standardised timepoints (1 week, 6 weeks, 3, 6, and 12 months) using count of PPD and nurse-supervised 24 h-PT. UI severity was classified as mild (<100 g), moderate (100-400 g), or severe (>400 g). Correlations were calculated using Spearman's ρ. The correlation between the PPD count and 24 h-PT was strong across all timepoints and increased over the postoperative year, from ρ = 0.77 at 1 week to 0.99 at 12 months. The overall correlation for all paired measurements was ρ = 0.94 (95% confidence interval 0.93-0.94). The median (interquartile range) 24 h-PT values rose consistently with increasing PPD count categories: from 15 (7-38) g for 1 pad/day to 781 (478-1200) g for ≥5 pads/day. At 12 months, 94% of men using one pad had urine loss <100 g, whereas 85% of those using ≥5 pads/day exceeded 400 g. Intermediate categories (2-4 pads/day) showed wide variability, limiting their discriminative value. The PPD count shows a strong correlation with 24 h-PT throughout the first postoperative year after RP. Use of 0-1 pad/day effectively excluded moderate-to-severe UI, whereas ≥5 pads/day reliably identified severe UI. The PPD count is a practical follow-up tool, while 24 h-PT remains necessary for patients using 2-4 pads/day.