Measuring health-related quality of life in colorectal cancer patients: systematic review of measurement properties of the EORTC QLQ-CR29.

INTRODUCTION: The EORTC QLQ-CR29 is a patient-reported outcome measure to evaluate health-related quality of life among colorectal cancer patients in research and clinical practice. The aim of this systematic review was to investigate whether the initial positive results regarding the measurement properties of the QLQ-CR29 are confirmed in subsequent studies.

METHODS: A systematic search of Embase, Medline, PsycINFO, and Web of Science was conducted to identify studies investigating the measurement properties of the QLQ-CR29 published up to January 2019. For the 11 included studies, data were extracted, methodological quality was assessed, results were synthesized, and evidence was graded according to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology on the measurement properties: structural validity, internal consistency, reliability, measurement error, construct validity (hypothesis testing, including known-group comparison, convergent and divergent validity), cross-cultural validity, and responsiveness.

RESULTS: Internal consistency was rated as "sufficient," with low evidence. Reliability was rated as "insufficient," with moderate evidence. Construct validity (hypothesis testing; known-group comparison, convergent and divergent validity) was rated as "inconsistent," with moderate evidence. Structural validity, measurement error, and responsiveness were rated as "indeterminate" and could therefore not be graded.

CONCLUSION: This review indicates that current evidence supporting the measurement properties of the QLQ-CR29 is limited. Additionally, better quality research is needed, taking into account the COSMIN methodology.