Diagnostic value of International Prostate Symptom Score voiding-to-storage subscore ratio in male lower urinary tract symptoms

Aims: To investigate the diagnostic value of the International Prostate Symptom Score (IPSS) voiding-to-storage subscore ratio (IPSS-V/S) in male lower urinary tract symptoms (LUTS). Methods: A total of 253 men with LUTS were enrolled from January 2005 to July 2010. The voiding (IPSS-V) and storage IPSS (IPSS-S) subscores were recorded separately by the patients themselves. The IPSS-V/S was calculated and compared among various aetiologies based on videourodynamic studies. Receiver operating characteristics (ROC) curves were constructed for comparing the diagnostic value of various non-invasive methods for predicting failure to voiding and storage lower urinary tract dysfunction (LUTD). Results: Patients with failure to voiding LUTD, including benign prostatic obstruction (n = 72), bladder neck dysfunction (n = 19), urethral stricture (n = 3) and poor relaxation of the urethral sphincter (n = 32), had mean IPSS-V/S scores > 1. In contrast, patients who were urodynamically normal (n = 2) or had failure to storage LUTD, including idiopathic detrusor overactivity (n = 84), increased bladder sensation (n = 37), and detrusor overactivity and impaired contractility (n = 4), had IPSS-V/S scores <= 1. When IPSS-V/S was used to differentiate male LUTS, failure to voiding LUTD was found in 81.2% of patients with IPSS scores > 1, while failure to storage LUTD was found in 75.7% of patients with IPSS-V/S <= 1. The area under ROC curve of IPSS-V/S was higher than for other non-invasive methods for predicting failure to voiding and storage LUTD. Conclusion: Measuring IPSS subscores and calculating IPSS-V/S is a simple and useful method to differentiate failure to voiding and failure to storage LUTD in men with LUTS. IPSS-V/S may provide a guide for the initial treatment, especially for primary care physicians without access to urological studies.