The efficacy of in-and-out catheterization as a way of trial without catheterization strategy for treatment of acute urinary retention induced by benign prostate hyperplasia: variables predicting success outcome.

Aim: To evaluate the efficacy and proper use of in-and-out catheterization as a strategy for trial without catheterization (TWOC) for treatment of acute urinary retention (AUR).

Methods: Retrospective analysis of 515 patients who visited the emergency room with AUR from January 2004 to December 2008 was conducted. Patients were segregated to one of two groups, depending on management of AUR (in-and-out catheterization at one time: Group 1 or indwelling catheter: Group 2). To characterize the optimal patient characteristics particularly fitting for Group 1 among each success subgroup, Fisher's linear discriminant analysis (LDA) was then conducted. Using an equation from LDA, the hit ratio was evaluated in a prospective trial from July to December 2009.

Results: TWOC success rate was 25.1% for Group 1 and 30.3% for Group 2. In successful cases, age, retention volume, and prostate sizes were significantly lower than those of failure counterparts in both Groups 1 and 2. Among these, age and retention volume were finally selected for LDA. When comparing successful cases, these two were significantly lower in Group 1 than Group 2. LDA showed an 81.6% hit ratio for cases with successful TWOC. In a prospective trial of 28 patients, using an equation from LDA, five of seven patients in Group 1 (71.4%) and 16 of 21 patients (76.2%) in Group 2 succeeded in their initial TWOC.

Conclusions: These results suggest the efficacy of in-and-out catheterization as a way of attempting TWOC, particularly for the patient with relatively low retention volume and younger age.