title: Incidence and risk of treatment for benign prostatic hyperplasia in Japanese men: a 15-year longitudinal community-based study.
abstract: OBJECTIVE
  To determine the incidence of and the risk factors for treatment in Japanese men with benign prostatic hyperplasia/lower urinary tract symptoms enrolled into a longitudinal community-based study.
  
  
  METHODS
  A total of 267 of 319 men aged 40-79 years were eligible for this study, with nearly 15 years of follow up. Their medical records were checked to look for any medical treatment for benign prostatic hyperplasia/lower urinary tract symptoms. The risk of treatment for benign prostatic hyperplasia/lower urinary tract symptoms was determined by calculating the hazard ratio using the Cox proportional hazards model. Five baseline parameters were considered: the International Prostate Symptom Score, the peak urinary flow rate, the prostate volume, the serum prostate-specific antigen and the internal prostatic architecture on transrectal ultrasonography.
  
  
  RESULTS
  Data were successfully collected for 171 men (64%; 121 survivors and 50 deceased). During approximately 1900 person-years of follow up, the overall incidence of treatment for benign prostatic hyperplasia/lower urinary tract symptoms was 15.4/1000 person-years. All five parameters were statistically significant predictors of future treatment for benign prostatic hyperplasia/lower urinary tract symptoms: International Prostate Symptom Score greater than 7 (hazard ratio 6.2, P < 0.001), prostate volume greater than 30 mL (hazard ratio 4.3, P = 0.002), peak urinary flow rate less than 12 mL/s (hazard ratio 4.4, P < 0.001), prostate-specific antigen greater than 1.4 ng/mL (hazard ratio 4.0, P < 0.001) and internal prostatic architecture group 3 (hazard ratio 3.2, P = 0.002).
  
  
  CONCLUSIONS
  Severity of lower urinary tract symptoms, decreased peak urinary flow rate, enlarged prostate volume, high prostate-specific antigen value and internal prostatic architecture at baseline are independent risk factors for treatment in Japanese men presenting with benign prostatic hyperplasia/lower urinary tract symptoms.
authors.affiliation: Department of Urology, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan.
authors.forename: Fumimasa
authors.initials: F
authors.lastname: Fukuta
authors.forename: Naoya
authors.initials: N
authors.lastname: Masumori
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Mori
authors.forename: Taiji
authors.initials: T
authors.lastname: Tsukamoto
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011470:Prostatic Hyperplasia / Q000453:epidemiology* / Q000628:therapy; D012307:Risk Factors