Responsiveness was similar between direct and mapped SF-6D in colorectal cancer patients who declined

Objectives: 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.

Study design and setting: 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.

Conclusion: 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.