Clinical and urodynamic characteristics of underactive bladder

There have no universally accepted criteria and have been established for classification of underactive bladder (UAB) at present. Thus, the study described the comprehensive clinical and urodynamic characteristics of UAB in patients with lower urinary tract symptoms. A total of 1726 patients (1259men and 467women; 6–88 years old) whowere admitted to our center with a diagnosis of UABwere included in this retrospective study. It was due to the type of rehabilitation hospital, so higher percentage of neurological patients were included. The demographics, clinical characteristics, and urodynamic recordings were reviewed. The clinical characteristics and urodynamic findings of UAB were further classified. For the etiologic analysis, UAB with aging and without clear causes accounted for 11.5% of cases (199/1726), UAB with bladder outflow obstruction accounted for 2.6% (45/1726), and UAB acting on the nerve pathway of the voiding reflex accounted for 84.6% (1460/1726). There were a number of cases (1.3% [22/1726]) which had > 2 factors assigned. For studies involving urodynamic findings and clinical symptoms, the percentage of patients with detrusor hyperreflexia with impaired contractility (DHIC), detrusor underactivity (DU), and acontractile detrusor (AcD) was 0.7%, 5.6%, and 93.7%, respectively. UAB can be classified into 4 types based on possible etiologic mechanisms (idiopathic, myogenic, neurogenic, and integrative). Based on urodynamic findings and symptoms, UAB can be classified into 3 types (DU, AcD, and DHIC). The classification of UAB can provide a reasonable basis for the future research. Abbreviations: AcD = acontractile detrusor, BOO = bladder outflow obstruction, DO = detrusor overactivity, DU = detrusor underactivity, DHIC= detrusor hyperreflexia with impaired contractility, ICS= International Continence Society, LUTD= lower urinary tract dysfunction, LUTS = lower urinary tract symptoms, OAB = overactive bladder, PFS = pressure-flow study, Pdet = detrusor pressure, SCI = spinal cord injury, UAB = underactive bladder.