Updated normative data for the EORTC QLQ-C30 in the general Dutch population by age and sex: a cross-sectional panel research study

Purpose The European Organisation for Research and Treatment of Cancer (EORTC) quality of life core questionnaire (QLQ-C30) is a validated and widely-used Patient-Reported Outcome Measure for measuring the health-related quality of life (HRQoL) of cancer patients. To facilitate interpretation of results obtained in studies using the EORTC QLQ-C30, we generated normative data for the Dutch general population, stratified by age and sex. Methods Dutch participants were selected from a larger cross-sectional online panel research study collecting EORTC QLQ-C30 general population normative data across 15 countries. EORTC QLQ-C30 raw scores based on a 4-point response scale were transformed to linear scores ranging from 0 to 100. Transformed scores were weighted based on the United Nations population distribution statistics and presented by age and sex/age. Differences in scale scores of ≥ 10 points in HRQoL were applied to indicate clinical relevance. Results One thousand respondents completed the online survey. Stratified by age, clinically meaningful differences were observed, with worse physical functioning scores and better emotional functioning scores with increased age. Symptom scores remained stable across age groups, except for small age differences observed for fatigue, nausea/vomiting, diarrhoea, and financial difficulties. Stratified by sex/age, men generally scored better for both functioning and symptoms. However, these differences were not clinically meaningful. Conclusions These updated normative EORTC QLQ-C30 for the Dutch general population can be used to better interpret HRQoL data obtained from Dutch cancer patients. Being part of a larger international study, these data can further be used for inter-country comparisons in multi-national studies.