This study aimed to develop a bladder outlet obstruction (BOO) risk score by integrating symptom scores, prostatic parameters, uroflowmetry parameters, intravesical prostatic protrusion, and prostatic urethral angle to enhance the diagnosis of BOO in men with lower urinary tract symptoms (LUTS).

A total of 355 men with LUTS were enrolled and divided into a training set (N = 285) and a validation set (N = 70). Videourodynamic studies were conducted to classify lower urinary tract dysfunctions into BOO and non-BOO groups, with the BOO group further subdivided into bladder neck dysfunction and benign prostate obstruction. Parameters were assigned scores of 0, 1, 2, or 3 based on their predictive specificity for BOO. The BOO risk score was constructed by summing the scores of seven variables related to symptoms, prostate characteristics, and uroflowmetry. The area under the curve (AUC) analysis was used to determine optimal cutoff values for diagnosing lower urinary tract dysfunctions.

Among the 355 participants, 234 (65.9%) were diagnosed with BOO, including 136 (38.3%) with bladder neck dysfunction and 98 (27.6%) with benign prostate obstruction. Other lower urinary tract dysfunctions included detrusor overactivity (10.4%), dysfunctional voiding (7.9%), poor external sphincter relaxation (7.3%), detrusor underactivity (3.9%), stable bladder (2.5%), and hypersensitive bladder (2%). A BOO risk score of ≥10 demonstrated a sensitivity of 0.822 and specificity of 0.656 for predicting benign prostate obstruction in the training set [AUC = 0.800 (0.741–0.859)] and a sensitivity of 0.80 and specificity of 0.64 in the validation set [AUC = 0.813 (0.701–0.925)].

Utilizing office-based diagnostic tools, including symptom scores, uroflowmetry, and prostate parameters, a BOO risk score was successfully established. A score of ≥10 can predict benign prostate obstruction with over 80% accuracy in men with LUTS who do not respond to initial medical treatment.