Mapping EORTC-QLQ-C30 onto EQ-5D-5L Index in Indonesian Cancer Patients

Area of Science:

• Health Economics
• Oncology
• Psychometrics

Background:

• The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) is widely used to assess cancer patient quality of life.
• The EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) is a standardized instrument for measuring health outcomes and generating utility values.
• A direct mapping between these instruments is valuable for health economic analyses.

Purpose of the Study:

• To develop and validate a mapping algorithm for converting EORTC QLQ-C30 scores into EQ-5D-5L utility values.
• To assess the predictive accuracy of the developed algorithm in a cancer patient population.

Main Methods:

• A cross-sectional study involving 300 hospitalized cancer patients at Dr. Kariadi Hospital, Semarang, Indonesia.
• Data collected using EORTC QLQ-C30 and EQ-5D-5L questionnaires.
• Ordinary Least Squares (OLS) regression was employed to develop two models for predicting EQ-5D-5L utility values.

Main Results:

• The highest functional domain score was 'emotional function' (mean: 85.89), and the highest symptom domain score was 'weakness' (mean: 36.21).
• Both models yielded a predicted utility value of 0.683.
• Model 2, using fewer domains, showed slightly better predictive accuracy with Mean Absolute Error (MAE) of 0.125 and Root Mean Square Error (RMSE) of 0.168, compared to Model 1's MAE of 0.128 and RMSE of 0.173.

Conclusions:

• A reliable mapping algorithm from EORTC QLQ-C30 to EQ-5D-5L utility values was successfully developed for cancer patients.
• Both models demonstrated similar predictive utility values, with Model 2 being more parsimonious.
• The algorithm facilitates utility value estimation, supporting health economic evaluations in cancer care.