Does Peak Urine Flow Rate Predict the Development of Incident Lower Urinary Tract Symptoms in Men with Mild to No Current Symptoms? Results from REDUCE.

PURPOSE: We determined whether decreased peak urine flow is associated with future incident lower urinary tract symptoms in men with mild to no lower urinary tract symptoms.

MATERIALS AND METHODS: Our population consisted of 3,140 men from the REDUCE (Reduction by Dutasteride of Prostate Cancer Events) trial with mild to no lower urinary tract symptoms, defined as I-PSS (International Prostate Symptom Score) less than 8. REDUCE was a randomized trial of dutasteride vs placebo for prostate cancer prevention in men with elevated prostate specific antigen and negative biopsy. I-PSS measures were obtained every 6 months throughout the 4-year study. The association between peak urine flow rate and progression to incident lower urinary tract symptoms, defined as the first of medical treatment, surgery or sustained and clinically significant lower urinary tract symptoms, was tested by multivariable Cox models, adjusting for various baseline characteristics and treatment arm.

RESULTS: On multivariable analysis as a continuous variable, decreased peak urine flow rate was significantly associated with an increased risk of incident lower urinary tract symptoms (p = 0.002). Results were similar in the dutasteride and placebo arms. On univariable analysis when peak flow was categorized as 15 or greater, 10 to 14.9 and less than 10 ml per second, flow rates of 10 to 14.9 and less than 10 ml per second were associated with a significantly increased risk of incident lower urinary tract symptoms (HR 1.39, p = 0.011 and 1.67, p <0.001, respectively). Results were similar on multivariable analysis, although in the 10 to 14.9 ml per second group findings were no longer statistically significant (HR 1.26, p = 0.071).

CONCLUSIONS: In men with mild to no lower urinary tract symptoms a decreased peak urine flow rate is independently associated with incident lower urinary tract symptoms. If confirmed, these men should be followed closer for incident lower urinary tract symptoms.