The relationship of the international prostate symptom score and objective parameters for diagnosing bladder outlet obstruction. Part I: When statistics fail

Purpose: We evaluated the International Prostate Symptom Score and correlated it with objective means of determining bladder outlet obstruction. Materials and Methods: Beginning in May 1996, 460 men 41 to 88 years old (mean age plus or minus standard deviation 60.4 +/- 9.4) were prospectively included in this study. Symptoms were evaluated using the International Prostate Symptom Score, and digital rectal examination, outpatient cystoscopy, prostate specific antigen determination and transrectal ultrasound were done. Urodynamic evaluation included uroflowmetry, filling cystometry and pressure flow study. Results: Linear regression was done to correlate scores with measurable parameters. We noted no correlation of the total, obstructive symptoms or irritative symptoms score with objective parameters, including the average and maximum flow rate, post-void residual urine, prostate size and Schafer grade. Conclusions: Prostatic symptom scores are qualitative. Using them to quantify the degree of obstruction or evaluate therapy is questionable.