Assessment of different continence definitions in the context of the randomized multicenter prospective LAP-01 trial-Does the best definition change over time?

backgroundA uniform definition of continence is urgently needed to allow the comparison of study results and to estimate patient outcomes after radical prostatectomy (RP). To identify a practical definition that includes both objective and subjective aspects in a tangible way, we assessed different continence definitions and evaluated which best reflects the patients' subjective perception of continence.

methodsOur analyses included 718 patients that underwent either robot-assisted radical prostatectomy (RARP) or laparoscopic radical prostatectomy (LRP) in a multicenter randomized patient-blinded trial. Continence was assessed through patient questionnaires prior to and at 3, 6 and 12 months after surgery which included the number of pads used per day, the ICIQ-SF and the question "Do you suffer from incontinence? (yes/no)" to assess subjective continence. We used Krippendorff's Alpha to calculate the agreement of different continence definitions with the subjective perception.

resultsAt 3 months, the "0/safety pad" definition shows the highest agreement by alpha = 0.70 (vs. 0.63 for "0 pads" and 0.37 for "0-1 pad"). At 6 and 12 months "0 pads" is the better match, with alpha values of 0.69 (vs. 0.62 and 0.31) after 6 months and 0.70 (vs. 0.65 and 0.32) after 12 months. The ICIQ-SF score shows good correlation with the subjective continence at 3 months (alpha = - 0.79), the coefficient then decreasing to - 0.69 and - 0.59 at 6 and 12 months.

conclusionThe best continence definition according to the patients' perspective changes over time, "0 pads" being the superior criterion in the long-term. We recommend using the 0-pad definition for standardized continence reporting, as it is simple yet as accurate as possible given the inevitably high subjectivity of continence perception. Trial registration The LAP-01 trial was registered with the U.S. National Library of Medicine clinical trial registry (clinicaltrials.gov), NCT number: NCT03682146, and with the German Clinical Trial registry (Deutsches Register Klinischer Studien), DRKS ID number: DRKS00007138.