Efficacy of urine loss ratio for prognosis of urinary continence after radical prostatectomy: A retrospective cohort study in a single Japanese institution

PURPOSE: The usefulness of the urine loss ratio in the early postoperative period for prognosis of long-term urinary continence after radical prostatectomy has not been fully determined. MATERIALS AND METHODS: All patients who underwent radical prostatectomy for prostate cancer at our institution between November 2015 and March 2021 were retrospectively included. We investigated the rate of continence achievement 1 year after surgery, as well as the associated risk factors for reduced continence achievement, classified by every 10% of the urine loss ratio. RESULTS: Of the 100 patients with available urine loss ratio data, 66 achieved urinary continence. Ninety-three percent of patients with urine loss ratios of ≤10%, 40%–75% of patients with urine loss ratios of 11%–80%, and 20%–36% of patients with urine loss ratios of >80%, achieved continence. The logistic regression analysis showed that the urine loss ratio severity, body mass index (BMI) of >25 kg/m(2), and smoking history were unfavorable to achieve urinary continence. A BMI of ≤25 kg/m(2) was favorable for urinary continence achievement, but only up to an 80% urine loss ratio. Nonsmokers achieved continence well, even with a urine loss ratio of >80%. CONCLUSIONS: Classifying patients into three groups based on their urine loss ratios is potentially useful for urinary continence prognosis. Smoking and obesity were risk factors for continued urinary incontinence, although the prognostic accuracy was expected to improve when considering the severity of the urine loss ratio.