Relationship among symptom score, prostate volume, and urinary flow rates in 543 patients with and without benign prostatic hyperplasia.Prostate 1998; 34(2):121-8; discussion 129P
Studies on the relationship among symptom score, urinary flow rate, and prostate volume in men with lower urinary tract symptoms (LUTS) continue to be of great interest.
A total of 2,418 men, aged 30-86 years, agreed to participate in an interview and to complete a questionnaire regarding voiding patterns. All subjects answering positively to one or more of the questions were submitted to a diagnostic assessment, based on the algorithm outlined by the guidelines of the International Consultation on Benign Prostatic Hyperplasia (BPH). Five hundred forty-three out of the 2,418 participants (22.45%) were evaluated. At the end of the diagnostic evaluation, 400 men with LUTS but without concomitant conditions (except BPH) known to interfere with normal voiding were selected. Descriptive statistics were used to characterize age, symptom score (International Prostate Symptom Score), prostate volume, and urinary flow rate distribution in these patients. Correlations among the aforementioned parameters were evaluated by means of a multivariate, multiple linear regression and logistic regression model.
As reported in other studies, only weak or modest correlations were found. Moreover, the 400 cases were classified according to four age decades. The decrease in peak and mean flow rate per decade of age was similar (0.5 and 0.4 ml/sec); the increase in prostate volume and in total symptom score per decade was 3.3 cc and 0.6, respectively. In patients less than 50 years old, most of the correlations were stronger than those observed in the entire population of 400 men (age and prostate volume, c.c. 0.2864; age and peak flow rate, c.c. -0.2689; age and mean flow rate, c.c. -0.3034). However, symptom score continued to be weakly correlated with age and prostate volume (c.c. 0.0498 and 0.1966, respectively). In the last part of the study, men were assigned to different treatment strategies. Patients who were assigned to surgical treatment had higher prostate volume and IPSS and lower urinary flow rate than those assigned to nonsurgical treatment.
We believe that the reason for the weak statistical association frequently reported in the literature is mainly the urology clinic-based population from which the patient samples were drawn. Data emerging from this analysis support the hypothesis that age is one of the principal factors influencing the relationship among symptom score, urinary flow rate, and prostate volume.