Construction of the Patient-Oriented Prostate Utility Scale (PORPUS): a multiattribute health state classification system for prostate cancer

Health status indexes, such as the EuroQol, consist of a health state class ification system and a set of utility weights. Indexes measure quality of l ife using a 0-1 utility score. Utilities for outcomes in prostate cancer (P C) are of unique importance, but generic indexes do not represent PC outcom es (e.g., sexual, urinary, bowel dysfunction) well, and may not capture the ir full impact. As a step toward improved utility measurement, we construct ed a classification system for PC, We generated items for each of six healt h domains and rated their importance using interviews with 10 clinical expe rts and 80 patients. Key concepts were selected for each domain using item importance weightings, and a set of predetermined criteria. Text was develo ped to express levels of severity within each domain. Experts and two addit ional groups of patients (n = 40, n = 96) evaluated textual clarity and end orsed the content validity of the instrument. The final system consists of 10 domains with 4-6 levels each. The content validity of the system was end orsed by patients and experts. In conjunction with a set of utility weights , it may be used to develop a health status index, to improve utility measu rement in patients, and to serve as a short psychometric (nonutility) instr ument. (C) 2000 Elsevier Science Inc. All rights reserved.