EORTC QLQ-C30 general population normative data for Italy by sex, age and health condition: an analysis of 1,036 individuals

General population normative values for the widely used health-related quality of life (HRQoL) measure, European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire - Core 30 (EORTC QLQ-C30), are available for a range of countries. These are mostly countries in northern Europe. However, there is still a lack of such normative values for southern Europe. Therefore, this study aims to provide sex-, age- and health condition-specific normative values for the general Italian population for the EORTC QLQ-C30. This study is based on Italian EORTC QLQ-C30 general population data previously collected in an international EORTC project comprising over 15,000 respondents across 15 countries. Recruitment and assessment were carried out via online panels. Quota sampling was used for sex and age groups (18‍-‍39, 40-49, 50-59, 60-69 and ≥ 70 years), separately for each country. We applied weights to match the age and sex distribution in our sample with UN statistics for Italy. Along with descriptive statistics, linear regression models were estimated to describe the associations of sex, age and health condition with the EORTC QLQ-C30 scores. A total of 1,036 respondents from Italy were included in our analyses. The weighted mean age was 49.3 years, and 536 (51.7%) participants were female. Having at least one health condition was reported by 60.7% of the participants. Men reported better scores than women on all EORTC QLQ-C30 scales but diarrhoea. While the impact of age differed across scales, older age was overall associated with better HRQoL as shown by the summary score. For all scales, differences were in favour of participants who did not report any health condition, compared to those who reported at least one. The Italian normative values for the EORTC QLQ-C30 scales support the interpretation of HRQoL profiles in Italian cancer populations. The strong impact of health conditions on EORTC QLQ-C30 scores highlights the importance of adjusting for the impact of comorbidities in cancer patients when interpreting HRQoL data.