ABSTRACT Purpose To identify how the most frequently used parameters in daily clinical practice diagnosing bladder outlet obstruction (BOO) due to benign prostate hyperplasia (BPH) correlate to each other. Materials and methods The study included 452 patients with lower urinary tract symptoms (LUTS) of the UNICAMP urology outpatient clinic of LUTS.

Inclusion criteria:

patients with BOO due to BPH who agreed to participate in the study.

Exclusion criteria:

patients with urinary tract infection, neurological diseases that compromised the lower urinary tract, prior prostatic surgery, radiotherapy or urethral stenosis.

Patient assessment:

history, international prostate symptoms score (IPSS), nocturnal quality of life score (NQoL) questionnaires, physical and digital rectal examination (DRE), PSA, transabdominal ultrasound with intravesical prostate protrusion (IPP), post-mictional residue and free uroflowmetry. Results There was no strong Spearman correlation among the studied variables. The only moderate correlations occurred between IPSS and NQoL (p <0001; c=0.56) and between IPP and prostate volume (p <0001; c=0.57). Weak correlations between IPP and post-mictional residue (p <0001; c=0.31) and free uroflowmetry (p <0001; c=-0.26); and between IPSS and free uroflowmetry (p <0001, c=-0.21) were observed. Conclusion In this study, we found moderate, weak, very weak and absent correlation among the various parameters used in the diagnosis and management of BOO due to BPH. As the value of these tools is variable, the creation of a logical and objective algorithm was not possible and the treatment is based on the interpretation of clinical symptoms.