Mapping the cancer-specific QLQ-C30 onto the generic EQ-5D-5L and SF-6D in colorectal cancer patients

ABSTRACT

Introduction: Economic evaluation of healthcare interventions usually needs accurate data on utility and health-related quality-of-life scores. The aim of this study is to map QLQ-C30 scale score onto EQ-5D-5L and SF-6D utility values in colorectal cancer (CRC) patients.

Methods: EQ-5D-5L, SF-6D, and QLQ-C30 were completed by 252 patients with CRC who were referred to three cancer centers in Tehran between May and September 2017. Moreover, OLS, Tobit, and CLAD models were used to predict EQ-5D-5L and SF-6D values. The goodness of fit of models was evaluated using Pred R² and Adj R². In addition, their predictive performance was assessed by MAE, RMSE, ICC, MID, and Spearman’s correlation coefficients between observed and predicted EQ-5D-5L and SF-6D values. Models were validated using a 10-fold cross-validation method.

Results: Considering the goodness of fit and predictive ability of models, the OLS Model 2 performed best for EQ-5D-5L (Adj R² = 58.09%, Pred R² = 58.93%, MAE = 0.0932, RMSE = 0.129) and the OLS Model 3 performed best for SF-6D (Adj R² = 54.90%, Pred R² = 55.62%, MAE = 0.0485, RMSE = 0.0634).

Conclusion: Our results demonstrated that algorithms developed based on OLS Models 1 and 2 are the best for predicted EQ-5D-5L and SF-6D values, respectively.

KEYWORDS:

• QLQ-C30
• EQ-5D-5L
• SF-6D
• colorectal cancer
• quality of life

Acknowledgments

The authors hereby bestow much gratitude to the chemotherapy and radiography departments of Imam Khomeini Hospital, Shohada Tajrish Hospital, and Shohada Haft-Tir Hospital for their valuable collaboration and participation in the present study. This report was funded by Tehran University of Medical Sciences and Iran National Science Foundation, as well as was approved by the ethics committee of the three selected centers.

Compliance with Ethical Standards

This report is part of a PhD project that was funded by Tehran University of Medical Sciences (registration number: 240/1938, and was approved by the ethics committee of the three selected centers). And the authors declare that they have no conflict of interest, and informed consent was obtained from participants.

Declaration of Interest

AA Sari discloses affiliation with the Iranian National Science Foundation and Tehran University of Medical Sciences. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer Disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Informed consent

Informed consent was obtained from all individual participants included in the study.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This study was funded by Tehran University of Medical Sciences (grant number 240/1938) and Iranian National Science Foundation.