Comparison of the clinical efficacy of medical treatment of symptomatic benign prostatic hyperplasia between normal and obese patients.

We aimed to investigate the difference in efficacy of medical treatment of symptomatic benign prostatic hyperplasia (BPH) between normal and obese patients with BPH; obesity was determined by either body mass index (BMI) or waist circumference (WC). In this 12-week prospective observational study, a total of 175 patients aged ≥40 years with International Prostate Symptom Scores (IPSS) ≥12 points and prostate volume ≥20 ml were prospectively enrolled. The patients were divided into two groups according to BMI or WC. Patients received the doxazosin gastrointestinal therapeutic system (GITS) at a dose of 4 mg once per day for 12 weeks. The changes from baseline in the IPSS, maximal urinary flow rate (Q(max)), post-void residual volume, quality of life (QoL) scores and adverse events (AEs) were analysed. Of the 175 enrolled patients, 132 completed the study. Sixty-seven patients had BMI >23 kg m⁻², and 43 had WC >90 cm. Obese patients represented by WC >90 cm or BMI ≥23 kg m⁻² had a significantly greater prostate volume compared with non-obese patients at baseline. Total IPSS was significantly higher in the WC >90 cm group compared to the WC ≤90 cm group. Total IPSS was positively correlated with prostate volume (P=0.031) and WC (P=0.045). All groups showed significant improvements in total IPSS and QoL at 12 weeks. However, the improvement of total IPSS was greater in the high-BMI and high-WC groups. The most frequent AE was dizziness (n=13), and it was significantly lower in the obese BPH patients. Obesity was associated with increased prostate volume and lower urinary tract symptoms. Alpha-blockers appear to be efficacious for controlling symptoms, especially in obese men.