Research Objectives, Statistical Analyses and Interpretation of Health-Related Quality of Life Data in Glioma Research: A Systematic Review

SIMPLE SUMMARY: Health-related quality of life (HRQoL) is an important outcome in glioma patients, as it reflects the patient’s perspective on their functioning and wellbeing through the disease course. The aim of our systematic review was to provide an overview of how HRQoL data is currently analyzed and interpreted in glioma studies. We found that the number of studies including HRQoL data increased in the past decade, but that assessment and analytical methods were highly variable. Ways to maximize information obtained with HRQoL questionnaires include appropriate and complementary analyses at both the group and individual level, comprehensive reporting of HRQoL results, and adherence to existing guidelines on the assessment, analysis, reporting and interpretation of patient-reported outcomes. This may ultimately result in high quality information that is relevant to inform physicians, patients and their relatives about the impact of the disease and its treatment on the patients’ functioning and well-being. ABSTRACT: Background: Health-related quality of life (HRQoL) has become an increasingly important patient-reported outcome in glioma studies. Ideally, collected HRQoL data should be exploited to the full, with proper analytical methods. This systematic review aimed to provide an overview on how HRQoL data is currently evaluated in glioma studies, focusing on the research objectives and statistical analyses of HRQoL data. Methods: A systematic literature search in the databases PubMed, Embase, Web of Science and Cochrane was conducted up to 5 June 2020. Articles were selected based on predetermined inclusion criteria and information on study design, HRQoL instrument, HRQoL research objective and statistical methods were extracted. Results: A total of 170 articles describing 154 unique studies were eligible, in which 17 different HRQoL instruments were used. HRQoL was the primary outcome in 62% of the included articles, and 51% investigated ≥1 research question with respect to HRQoL, for which various analytical methods were used. In only 42% of the articles analyzing HRQoL results over time, the minimally clinical important difference was reported and interpreted. Eighty-six percent of articles reported HRQoL results at a group level only, and not at the individual patient level. Conclusion: Currently, the assessment and analysis of HRQoL outcomes in glioma studies is highly variable. Opportunities to maximize information obtained with HRQoL data include appropriate and complementary analyses at both the group and individual level, comprehensive reporting of HRQoL results in separate articles or supplementary material, and adherence to existing guidelines about the assessment, analysis and reporting of patient-reported outcomes.