Clinical predictors of bladder outlet obstruction in men consulting for routine urological screening

Lower urinary tract symptoms (LUTS) associated with bladder outlet obstruction (BOO) are prevalent among men, notwithstanding being self-underreported. We aimed to assess the predictors for BOO during first visit.

Data from 1045 analyzed men older than 40 years attending a single urological institution from 2010 to 2021. The men diagnosed with BOO, prostate cancer or any treatment for BOO were excluded. The patients completed the International Prostatic Symptoms Score (IPSS) and were investigated with prostate-specific antigen (PSA), trans-rectal ultrasound to measure prostate volume (PV) and free uroflowmetry. Logistic regression analysis tested the association between parameters and BOO. The area under the curve compared the diagnostic accuracy of predictors. The Youden-index analysis defined the cut-off predicting LUTS.

Of 1045 patients, the median (IQR) age was 62 (51-69) years. A total of 773 (74%) had moderate LUTS. Both PV (OR: 1.16; 95%CI 1.04-1.3; p = 0.005) and IPSS (OR: 1.06; 95%CI 1.03-1.08; p < 0.001) were associated with BOO after adjusting for age. They showed a predictive accuracy with an AUC of 0.69 (0.60-0.77) and 0.63 (0.59-0.67) for PV and IPSS, respectively. A PV of 43 mL emerged as the cut-off point to define the risk of BOO. Therefore, a 60-year man with a PV ≥ 43 mL showed an 84% (70-90) risk of BOO as compared with 59% (50-68) for a same age man with lower PV.

Men older than 40 years should be screened for LUTS associated with BOO since they are highly prevalent. User-friendly parameters such as PV and IPSS could guide further investigation of BOO.