Overactive bladder changes with time: a 5-year longitudinal followup of changes in overactive bladder symptoms, urodynamic studies and urinary nerve growth factor levels.

Abstract

We compared clinical symptoms, urodynamic diagnoses and urinary nerve growth factor levels at baseline and 5 years later in patients with overactive bladder. Patients diagnosed with overactive bladder at a tertiary teaching hospital who underwent urinary nerve growth factor tests 5 years previously were identified by chart review. Patients were invited to return for symptom evaluation, urodynamic studies and a repeat urinary nerve growth factor test. Changes in overactive bladder subtype, urgency severity score and urodynamic diagnosis were classified as improved, stable or worse. Changes in urinary nerve growth factor/creatinine were compared between baseline and 5 years later according to changes in bladder conditions. A total of 30 women and 45 men completed the study. Mean±SD age was 73.5±10.3 years. Urinary nerve growth factor/creatinine showed no significant difference among patients with improved, stable or worse bladder conditions based on overactive bladder or urgency severity score subtypes. However, urinary nerve growth factor/creatinine was significantly decreased in patients with an improved urodynamic diagnosis (mean 0.94±1.36 vs 0.17±0.19 pg/mg, p=0.02), significantly increased in patients with a worse urodynamic diagnosis (0.55±0.85 vs 2.08±2.81 pg/mg, p=0.04) and showed no change in those with a stable urodynamic diagnosis. Multiple linear regression analysis revealed that the change in urodynamic diagnosis was still predictive of the change in urinary nerve growth factor/creatinine after adjusting for age, gender, overactive bladder and urgency severity score subtypes (p=0.001). Urinary nerve growth factor/creatinine did not reflect the changes in bladder conditions based on subjective symptoms. However, the levels reflected dynamic changes in bladder pathophysiology according to urodynamic findings.