Abstract
Aim
To use published literature and experts’ opinion to investigate the clinical meaning and magnitude of changes in the Quality of Life (QOL) of groups of patients measured with the European Organisation for the Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30).
Methods
An innovative method combining systematic review of published studies, expert opinions and meta-analysis was used to estimate large, medium, and small mean changes over time for QLQ-C30 scores.
Results
Nine hundred and eleven papers were identified, leading to 118 relevant papers. One thousand two hundred and thirty two mean changes in QOL over time were combined in the meta-analysis, with timescales ranging from four days to five years. Guidelines were produced for trivial, small, and medium size classes, for each subscale and for improving and declining scores separately. Estimates for improvements were smaller than respective estimates for declines.
Conclusions
These guidelines can be used to aid sample size calculations and interpretation of mean changes over time from groups of patients. Observed mean changes in the QLQ-C30 scores are generally small in most clinical situations, possibly due to response shift. Careful consideration is needed when planning studies where QOL changes over time are of primary interest; the timing of follow up, sample attrition, direction of QOL changes, and subscales of primary interest are key considerations.
To use published literature and experts’ opinion to investigate the clinical meaning and magnitude of changes in the Quality of Life (QOL) of groups of patients measured with the European Organisation for the Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30).
Methods
An innovative method combining systematic review of published studies, expert opinions and meta-analysis was used to estimate large, medium, and small mean changes over time for QLQ-C30 scores.
Results
Nine hundred and eleven papers were identified, leading to 118 relevant papers. One thousand two hundred and thirty two mean changes in QOL over time were combined in the meta-analysis, with timescales ranging from four days to five years. Guidelines were produced for trivial, small, and medium size classes, for each subscale and for improving and declining scores separately. Estimates for improvements were smaller than respective estimates for declines.
Conclusions
These guidelines can be used to aid sample size calculations and interpretation of mean changes over time from groups of patients. Observed mean changes in the QLQ-C30 scores are generally small in most clinical situations, possibly due to response shift. Careful consideration is needed when planning studies where QOL changes over time are of primary interest; the timing of follow up, sample attrition, direction of QOL changes, and subscales of primary interest are key considerations.
| Original language | English |
|---|---|
| Pages (from-to) | 1713-1721 |
| Number of pages | 9 |
| Journal | European Journal of Cancer |
| Volume | 48 |
| Issue number | 11 |
| Early online date | 12 Mar 2012 |
| DOIs | |
| Publication status | Published - Jul 2012 |
Bibliographical note
Role of the funding sourceCancer Research UK funded the study [Grant No. C7852/A5653] and a UICC ICRETT fellowship provided a travel and subsistence grant to K.C. at the start of the study. The funders had no role in the design and conduct of the study; the collection, management, analysis and interpretation of data; the writing of the manuscript; or the decision to submit the manuscript for publication. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.
Keywords
- EORTC QLQ-C30
- Statistical data interpretation
- Quality of Life
- Longitudinal studies
- Meaningful difference
- Minimally important difference
- Sample size
