The long-term changes of symptoms in Overactive bladder (OAB) patients are not fully understood. The purpose of this study is to analyze the severity of OAB symptoms and symptom-specific bother in long term and investigate the prognostic factors of symptomatic change.

We retrospectively analyzed hospital record of female patients who visited our clinic from January 2008 to December 2014 and were diagnosed as OAB. The severity of OAB symptoms and the bother specific to each OAB symptom were assessed using 2 questionnaires the OAB symptom score (OABSS) (#1) and the visual analogue scale (VAS) questionnaires for each OABSS (OABSS-VAS)(#2), respectively.

This study was conducted with the approval of the institutional ethical committee.
We had 613 female OAB patients in those seven years. Among those patients, we analyzed patients in detail with whom we could observe more than 3 years and compare OABSS and OABSS-VAS before and after treatment. In those patients, the median (range) age was 71 (22-87) years. and the median follow-up period was 67(36-130) months. The number of wet OAB patients was 85 and that of dry OAB was 7. Median number of past usage of anti-muscarinic agents was 3 (0-6) and 62 patients had previous history of usage of mirabegron. In comparison of symptom and bother/QOL scores between before and after treatment, there were significant improvement in symptom scores, including OABSS-nocturia (Q2) (p=0.0057), OABSS-urgency (Q3) (p<0.0001), OABSS-urge incontinence (Q4) (p=0.0002), and total scores of OABSS (p<0.0001); similarly, there were significant improvement in QOL/bother scores including VAS- daytime frequency (Q1) (p=0.0009), VAS-nocturia (Q2) ( p=0.0201), VAS-urgency (Q3) (p<0.0001), VAS-urge incontinence (Q4) (p=0.0003)), respectively. We found also significant improvement of VAS-QOL score(p<0.0001). Among wet OAB patients, 71 patients (83.5%) suffered from UUI after OAB treatment. On the other hand, UUI was disappeared in 14 patients (16.5%) of wet OAB patients. Among dry OAB patients, UUI was newly occurred in 5 patients (71.4%). According to OABSS, in 25 patients (27.2%) total OABSS score were increased after treatment and in 10 patients (10.9%) disease severity were increased (Fig.1a). When taking account of the past history in relation to the OAB symptom or QOL,there were no significant correlations of symptomatic aggravation with age, treatment period, and co-existing disease such as hypertension, DM, cerebral vascular disease. However, we found significant correlations between OAB symptomatic aggravation and co-existing cardiovascular disease (p=0.008) (Fig.1b).

There were few reports about long-term (>12 months) outcome in OAB treatment. Our study showed symptomatic change of OAB during over a 5-year follow-up.  In our study, as in Fig.2, the decrease in OABSS and OABSS-VAS score has been demonstrated at the beginning of the treatment with maintaining of the decreased score with only small fluctuations.  However, in 25 patients (27.2%) total OABSS score were increased during the follow-up and in 10 patients (10.9%) disease severity were increased. Interestingly, there were significant correlations between OAB symptomatic aggravation and co-existing cardiovascular disease (p=0.008), while no significant correlations with treatment period or age. As reported, the prevalence of cardiovascular comorbidities was significantly higher in patients with than without OAB (#3), the patients who has cardiovascular disease may have the risk for treatment-resistance against OAB.

At a mean follow up of approximately 5.5 years, the OAB symptom severity were getting better in about 40% of OAB patients; while getting worse in about 10% of OAB patients despite undergoing various kinds of drug treatment. Patients who has cardiovascular disease may have the risk of treatment-resistant against OAB.

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