From Prostate Health to Overactive Bladder: Developing a Crosswalk for the IPSS to OAB-V8

Abstract Objectives To develop a statistical model to facilitate the comparison of 2 common patient-reported outcome (PRO) instruments in male lower urinary tract symptoms. Methods Two PROs used by urologists are the International Prostate Symptoms Severity (IPSS) and the Overactive Bladder-Validated 8 questions (OAB-V8). The former measures symptoms related to prostate cancer, the latter measures the severity of symptoms related to OAB. Ordinary least squares regression was used to develop 3 models for translating responses to the IPSS into OAB-V8 scores. The root mean square error was used to compare the models. Results The sample consisted of 493 participants, ranging from 18 to 93 years of age. The recommended model included the individual responses to the IPSSʼ items and participantsʼ age. Due to the low root mean square error (0.7606), indicating low variation and high precision, we can explain about 63% (R2 = 0.6260) relationship between IPSS and OAB-v8. Conclusion This study successfully modeled global OAB-V8 scores from IPSS responses. This model performed comparably well to others developed using similar methods.