Significant relationship of time-dependent uroflowmetric parameters to lower urinary tract symptoms as measured by the International Prostate Symptom Score

AIMS: The aim of the present paper is to elucidate the possible involvement of time-dependent parameters as obtained by uroflowmetry in the manifestation of lower urinary tract symptoms (LUTS) in elderly patients. METHODS: Using simple and multiple regression analyses, the correlation of the International Prostate Symptom Score (IPSS) with objective parameters including age, postvoid residual, uroflowmetry and transrectal ultrasonic measurements of the prostate was analyzed in 206 male patients (average age of 68.0 +/- 7.4 years) who visited our outpatient clinic complaining of LUTS. RESULTS: In the 206 patients, the mean maximum flow rate was 12.2 mL/s (13.7 mL/s in mild, 11.9 mL/s in moderate, and 11.2 mL/s in severe IPSS total score) and average flow rate was 4.4 mL/s (5.4 mL/s in mild, 4.3 mL/s in moderate, and 3.5 mL/s in severe IPSS total score). Simple regression analyses demonstrated that age, voiding time, and average and maximum flow rates correlate significantly with symptom scores. In particular, relatively strong relationships were found between average flow rate and scores of intermittency, weak stream and total and voiding symptoms scores. Serum prostate specific antigen level, postvoid residual and prostatic ultrasonic measurements did not show a significant correlation with symptom scores. Multiple regression analyses revealed age and average flow rate to be independent determinants for symptom scores. These results suggest that the time-dependent function in micturition interferes in the manifestation of LUTS in elderly men who have borderline or pathologic maximum flow rate. When evaluating uro flowmetry in elderly male patients with LUTS, attention should be paid to time-dependent parameters such as voiding time and average flow rate.