Abstract

Objective

To construct and validate a prediction model of preference-adjusted health status (EQ-5D) for metastatic hormone-refractory prostate cancer (HRPCA) patients using cancer-specific health-related quality of life (HRQoL) measures.

Methods

Data were obtained from a multicenter, multinational observational study of metastatic HRPCA patients conducted during 2002 to 2004. In addition to clinical and resource utilization, preference-adjusted health status (EQ-5D) and HRQoL (Functional Assessment of Cancer Therapy—Prostate [FACT-P] and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire [EORTC QLQ-C30]) data were collected. Predictive validity of ordinary least square (OLS) and median regressions of various model specifications were tested using cross-validation samples. The selected specification was thenfurther refined and tested for alternative model specifications and restrictions.

Results

OLS regression with both HRQoL measures as individual components and patient demographics was the best-performing model. It explained 58.2% of the observed EQ-5D variation in the validation sample. A model including only the prostate cancer-specific HRQoL measure, FACT-P, explained 53.5% of the observed EQ-5D variation.

Conclusion

The models developed have good predictive validity. These algorithms enable researchers to translate cancer-specific HRQoL measures to preference-adjusted health status in metastatic HRPCA patients. The findings will help perform health status adjustments in cost-utility analyses.