What Happened to All the Patients? Event Charts for Summarizing Individual Patient Data and Displaying Clinically Significant Changes in Quality of Life Data

Abstract

Purpose of Research: Event charts are a novel way of presenting data from pharmaceutical phase 1 clinical trials. We applied event chart methodology to summarize clinically significant changes in quality of life (QOL) data over time for oncology patients enrolled in North Central Cancer Treatment Group and Mayo Clinic Cancer Center clinical trials. Methods: Recent developments in QOL research have led to a number of definitions for clinically significant changes in oncology QOL measures. Many approaches suggest that on a 0 to 100 point scale, changes of<10 are small, 10 to 20 are moderate, and more than 20 points are large differences in QOL scores. This taxonomy is analogous to the tracking methodology invoked for the monitoring of toxicity data via National Cancer Institute Common Toxicity Criteria guidelines. This categorization was combined with event chart methodology to summarize QOL data over time for patients enrolled in oncology clinical trials. Event charts were compared to both the scatter plot approach and Kaplan-Meier time-to-event graphical representations. Results: The event chart method proved superior to plotting raw scores over time since atrisk individuals were identified with greater facility and censored or missing data were incorporated more readily due to the intent-to-treat nature of this method. Furthermore, event charts identified time points where patients may have experienced potential crises in QOL and where interventions could be employed. Conclusions: The event chart provides an innovative method for summarizing individual patient QOL data over time. This methodology has the potential for use as a tracking device in oncology clinical trials. In this sense, we can record QOL "events" and potentially intervene based upon the observed magnitude of changes in scores.