title: Responsiveness was similar between direct and mapped SF-6D in colorectal cancer patients who declined.
abstract: OBJECTIVE
  To evaluate the responsiveness of generic and mapped preference-based measures based on the anchor of global change in health condition of colorectal cancer (CRC) patients.
  
  
  METHODS
  A baseline sample of 333 Chinese CRC patients was recruited between September 2009 and July 2010 and was surveyed prospectively at 6-month follow-up. Preference-based indices were derived from the generic SF-6D measure (SF-6DDirect), from the Short Form-12 (SF-6DSF-12), and mapped from the condition-specific Functional Assessment of Cancer Therapy-Colorectal (SF-6DFACT-C). Responsiveness of three measures was assessed using standardized effect size, standardized response mean, responsiveness statistic, and receiver operating characteristic (ROC) curve analysis.
  
  
  RESULTS
  The SF-6DSF-12 and SF-6DFACT-C indices were significantly more responsive to detect positive changes than the SF-6DDirect index in improved groups. In worsened group, the SF-6DDirect and SF-6DFACT-C indices showed significant decline from baseline to 6-month follow-up. The areas under the ROC curve for SF-6DDirect and SF-6DFACT-C indices were not statistically different from 0.7. The SF-6DFACT-C index was more responsive to changes in health status compared with other indices.
  
  
  CONCLUSIONS
  Direct SF-6D measure was more responsive than mapped preference-based measures in improved group but the direction was reversed in worsened group. The use of a preference-based index mapped from a condition-specific measure captures both negative and positive important changes among CRC.
authors.affiliation: Department of Family Medicine and Primary Care, The University of Hong Kong, 3/F, Ap Lei Chau Clinic, 161 Ap Lei Chau Main Street, Ap Lei Chau, Hong Kong. Electronic address: carlosho@hku.hk.
authors.forename: Carlos K H
authors.initials: CK
authors.lastname: Wong
authors.affiliation: Health Economics and Decision Science, ScHARR, The University of Sheffield, Sheffield, UK.
authors.forename: Brendan
authors.initials: B
authors.lastname: Mulhern
authors.affiliation: Department of Family Medicine and Primary Care, The University of Hong Kong, 3/F, Ap Lei Chau Clinic, 161 Ap Lei Chau Main Street, Ap Lei Chau, Hong Kong.
authors.forename: Yuk-Fai
authors.initials: YF
authors.lastname: Wan
authors.affiliation: Department of Family Medicine and Primary Care, The University of Hong Kong, 3/F, Ap Lei Chau Clinic, 161 Ap Lei Chau Main Street, Ap Lei Chau, Hong Kong.
authors.forename: Cindy L K
authors.initials: CL
authors.lastname: Lam
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000523:psychology* / Q000628:therapy*; D005260:Female; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D057240:Patient Preference; D011594:Psychometrics; D011788:Quality of Life; D012372:ROC Curve
keywords: Anchor; Colorectal cancer; Mapping; Preference-based; Responsiveness; SF-6D