Clinical characteristics and useful signs to differentiate detrusor underactivity from bladder outlet obstruction in men with non‐neurogenic lower urinary tract symptoms

Abstract

ObjectiveTo investigate the clinical characteristics and useful signs to differentiate detrusor underactivity from bladder outlet obstruction in men with non‐neurogenic lower urinary tract symptoms.MethodsA total of 638 treatment‐naive men with non‐neurogenic lower urinary tract symptoms who underwent subjective and objective evaluations were reviewed retrospectively. We divided the patients into detrusor underactivity and bladder outlet obstruction groups based on urodynamic findings, and compared parameters obtained from questionnaires and non‐invasive tests. Detrusor underactivity was defined as bladder contractility index ≤100 and bladder outlet obstruction index ≤40, whereas bladder outlet obstruction was defined as bladder contractility index >100 and bladder outlet obstruction index >40.ResultsOf 638 patients, 145 (22.7%) had detrusor underactivity and 273 (42.8%) had bladder outlet obstruction. Total international prostate symptom score and international prostate symptom score‐voiding subscore were significantly higher in the detrusor underactivity group. There were significant differences in prostate volume, intravesical prostatic protrusion, and all uroflowmetry parameters between the two groups. In multivariate logistic regression analysis, lower intravesical prostatic protrusion (cut‐off value 8.2 mm), lower bladder voiding efficiency (cut‐off value 70%), and the presence of sawtooth and interrupted waveform on uroflowmetry were significant predictive factors for detrusor underactivity. In particular, the incidence of sawtooth and interrupted waveform was significantly higher in the detrusor underactivity group (80%) than in the bladder outlet obstruction group (12.8%), which showed both high sensitivity (80%) and specificity (87.2%) in differentiating detrusor underactivity from bladder outlet obstruction.ConclusionsSawtooth and interrupted waveform on uroflowmetry can be a useful predictive factor for detrusor underactivity. In addition, lower intravesical prostatic protrusion and bladder voiding efficiency can be of supplementary use.

Clinical diagnostic criteria for detrusor underactivity: A report from the Japanese Continence Society working group on underactive bladder

“…Recently, Matsukawa et al focused on characteristic waveforms on uroflowmetry in men with DU. 9 They found that incidence of a sawtooth and interrupted waveform was significantly higher in the DU group (80%) than that in BOO group (12.8%). Multivariate logistic regression analysis revealed that the presence of this waveform was a significant predictive factor for DU with both high sensitivity (80%) and specificity (87.2%) in differentiating DU from BOO.…”

“…Maximum flow rate (Qmax) was shown to be significantly lower among patients with DU than in those with BOO. 6,7,9 However, multivariate logistic regression analysis failed to demonstrate that Qmax is a significant predictor of DU. In addition, Osman et al 1 listed three different cut-off values of Qmax that were used for urodynamic diagnostic criteria: less than 10, 12, and 15 mL/s.…”

“…It has been reported that PVR was significantly larger in men with DU than in those with BOO. [6][7][8][9] Based on multivariate logistic regression analysis, PVR was found to be an independent predictor of DU. 7,8 However, the cut-off value of PVR for predicting DU differs among studies, for example, 147 vs 84.5 mL reported by Lee et al 7 and Luo et al, 8 respectively.…”

“…They suggested an optimal cut-off value of 8.2 mm, which yielded a sensitivity of 77% and a specificity of 73%. 9…”

“…The cut-off values of predictors were determined on the basis of expert opinion as well as by considering evidence from the relevant literature. 1,[6][7][8][9][10][16][17][18] The proposed criteria include: Table 1.…”