Does the direction of change (better or worse) matter? A reanalysis of evidence

Abstract

INTRODUCTION: Health outcomes in oncology have broadened to now include the concept of patient-reported, health-related quality of life (HRQOL). Numerous reliable and well-validated measures are available to choose from, including the Functional Assessment of Cancer Therapy (FACT) measurement system. An important next step in the advancement of the field is translating HRQOL scores into clinically meaningful outcomes for patients, clinicians, and researchers. SIGNIFICANCE: In this study we sought to refine our understanding of clinically meaningful change in HRQOL scores of cancer patients, paying particular attention to the meaning of the direction of change. An earlier study asked patients to first indicate whether they experienced a change in their HRQOL, and if so, to rate the degree of change on a -/-point scale. Overall, patients who reported worsening of HRQOL had considerably larger mean change scores than those who reported improvements. A large percentage of patients reported experiencing no change in HRQOL (46%-63%), yet some of them also (unexpectedly) rated some degree of change. Based on these findings, we hypothesized that the direction of the change would be an important determining factor in patients’ assessment of the meaningfulness of the change. OBJECTIVE: To better understand conflicting responses and to determine whether such findings might be measurement related, we sought to replicate the findings of the first study using a further modification of a global rating of change (GRC) scale, revising it to be a single 15point scale. We also examined the relationship between GRC and the FACT Trial Outcome Index (TOI), which is a combination of the physical and functional well-being subscales along with disease-specific questions. METHODS: We assessed patients with cancer using the FACT-General (FACT-G) instrument with disease-specific additional concerns and an adapted GRC scale. The FACT-G, a measure designed for patients with any form of cancer, contains 27 questions comprising 4 primary HRQOL domains: physical, social/family, functional, and emotional well-being. Disease-specific additional concern subscales contain 7 to 12 items for each of 5 diagnoses (breast, colorectal, lung, head and neck, and prostate cancer). The FACT generates scores for each