Objective: To evaluate treatment failure during a 4-year follow-up period after administration of naftopidil for patients with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) in real-life clinical practice.
Material and methods: A total of 247 patients with LUTS/BPH who had an International Prostate Symptom Score (IPSS) of > or =8 were enrolled in the study. Naftopidil, 50 mg/day, was given to the patients. They were followed for 4 years with periodic evaluation. Treatment failure was defined as conversion to other medical treatment or to surgery.
Results: Of the 247 patients, treatment failure occurred in 42 (17.0%) during the 4-year follow-up period. The 4-year treatment failure rate was on the Kaplan-Meier curve 35.0%. Among parameters assessed at baseline, prostate volume (PV) was the only significant determinant of treatment failure: patients with a PV of > or =35 ml had a 2.1 times higher hazard of treatment failure than those with a PV of <35 ml (95% CI 1.06-4.33; p=0.03). Patients with a severe IPSS at 12 weeks after administration of naftopidil had a 3.5 times higher hazard than those having a mild/moderate IPSS (95% CI 1.34-9.26; p=0.01). After 4 years, 200 patients (81%) had stopped taking naftopidil because of adverse events, treatment failure, loss to follow-up, etc.
Conclusions: There were significant improvements in IPSS and urinary flow rate with naftopidil although it is unknown whether these improvements were significantly larger than the placebo effect as the study was non-randomized. However, only 19% of patients were known to have continued with the same medication for 4 years in real-life clinical practice. Patients who have a large prostate at baseline and a severe IPSS at 12 weeks after treatment are more likely to have treatment failure, although a prospective study is needed to confirm this.