Reference values for the EORTC QLQ-C30 quality of life questionnaire in a random sample of the Swedish population

Aim. To obtain reference values for health-related quality of life (HRQL) measured with the European Organization for Research and Treatment of Cancer (EORTC) Core Quality of Life Questionnaire (QLQ-C30) in a random sample of the adult Swedish population. Methods. A population-based survey of a random sample of 7002 Swedish adults aged 40-79 years, frequency-matched to reflect the age and sex distribution of upper gastrointestinal cancer patients. Scales were scored on a 0-100 metric according to standard procedures. Functions and symptoms were dichotomized into "poor" versus "good" function, and "symptomatic" and "no or minor symptoms", respectively. The results were stratified for age and gender. Results. The questionnaire was completed by 4910 (70.5%) of 6969 eligible participants. Missing values were limited. HRQL was found to vary according to age and sex. Generally, men reported better functioning and fewer symptoms than women. The most common symptoms were fatigue, pain, and insomnia. Conclusion. The reference values provided can be used as a surrogate baseline measure in HRQL research, and when evaluating the effect of interventions on HRQL in cancer patients.