Responsiveness of disease-specific and generic utility instruments in prostate cancer patients Murray Krahn 1,2,8 , Karen E. Bremner 1 , George Tomlinson 1,4,5 , Paul Ritvo 3,6 , Jane Irvine 3,7 & Gary Naglie 1,5 1 Department of Medicine, University of Toronto, Toronto, Ontario, Canada; 2 Faculty of Pharmacy, University of Toronto, Toronto, Canada; 3 Department of Psychology, University of Toronto, Toronto, Canada; 4 Department of Public Health Sciences, University of Toronto, Toronto, Canada; 5 Department of Health Policy, Management, and Evaluation, University of Toronto, Toronto, Canada; 6 Ontario Cancer Institute, Toronto, Ontario, Canada; 7 York University, Toronto, Canada; 8 The Toronto General Hospital, EN14-207, 200 Elizabeth Street, Toronto, Ontario, M5G 2C4, Canada Accepted in revised form 20 September 2006 Abstract Background: Preferences (utilities) for health outcomes have an important role in decisions about prostate cancer screening and treatment. The responsiveness of utility instruments has not been evaluated. Subjects: Prostate cancer outpatients from the Princess Margaret Hospital, Toronto (n = 248) were allocated into three cohorts: N – newly diagnosed and treated; M – metastatic disease; O – all others. Measures: We measured quality of life at 3 points within 12 months using 3 disease-specific utility instruments (Patient Oriented Prostate Utility Scales), 3 generic utility instruments (Health Utilities Index, EQ-5D, Quality of Well-Being Scale), and 3 profile scales (PORPUS-P profile, Prostate Cancer Index, QLQ-C-30). Respon- siveness was assessed using measures of internal responsiveness (standardized effect size, standardized response mean) and external responsiveness (receiver operator curve analysis, mixed model regression). Results: Cohort N patients showed post-treatment declines followed by improvement in global health and functional status. Disease specific instruments detected moderate (0.4–1.3) decrements followed by small increments (0.1–0.4) in standardized effect size and standardized response mean. Most instruments detected change using external responsiveness measures (all cohorts). Conclusions: Disease-specific utility instru- ments appeared to be more responsive than generic instruments. Use of generic instruments should be supplemented with a responsive disease-specific instrument, particularly for applications in early prostate cancer. Key words: Measurement, Psychometrics, Urologic diseases, Utility measurement Abbreviations: AUROC – area under the receiver operator curve; EQ-5D – EuroQol 5 dimension quality of life instrument; HRQL – health related quality of life; HUI – Health Utilities Index; PCI – Prostate Cancer Index; PORPUS – Patient Oriented Prostate Utility Scales; PORPUS I – health index version of PORPUS; PORPUS P – health profile version of PORPUS; PORPUS RS – direct utility elicitation version of the PORPUS, using rating scale scaling; PORPUS SG – direct utility elicitation version of the PORPUS, using standard gamble scaling; QLQ-C30 – European Organisation for the Research and Treatment of Cancer quality of life questionnaire, core module; QWB – Quality of Well Being Scale; RS – rating scale; SES – standardized effect size; SG – standard gamble; SRM – standardized response mean Quality of Life Research (2007) 16:509–522 Ó Springer 2006 DOI 10.1007/s11136-006-9132-x