How correlated is BOO with different objective parameters commonly used in evaluation of BPH: a prospective study

The use of non-intubated uroflowmetry, PVR, prostate volume, and I-PSS are the most commonly used tools for the evaluation of patients with BPH. In this prospective study, we elucidated the correlation between BOO as rated by pressure-flow study in men with LUTS attributed to BPH and those parameters.

Over a period of 2 years 460 men above the age of 45 years old (mean age 60.46 ± 9.4) were prospectively included in this study. Symptoms were evaluated using the International Prostate Symptom Score, and digital rectal examination, prostate-specific antigen, and transrectal ultrasound were done. The urodynamic evaluation included uroflowmetry, filling cystometry, and voiding cystometry with the plotting of pressure-flow study according to Lin-PURR (Schäfer's nomogram). The correlation coefficient was calculated between these variables.

The correlation of other objective parameters with total score was not much better. The Spearman's correlation coefficient were - 0.09, 0.07 and - 0.1 for prostate weight, post voiding residual urine and maximum free flow rate respectively. Correlations between Schäfer's grade and Q_max, PVR and prostate volume were found to be weak to fair correlation (r values were - 0.4, 0.18, and 0.39 respectively).

Objective non-invasive parameters most commonly used in the evaluation of men with LUTS attributed to BPH have limited correlation with obstruction, as diagnosed by pressure flow nomogram.