Minimally important differences for interpreting EORTC QLQ-C30 change scores over time: A synthesis across 21 clinical trials involving nine different cancer types

INTRODUCTION

Early guidelines for minimally important differences (MIDs) for the EORTC QLQ-C30 proposed ≥10 points change as clinically meaningful for all scales. Increasing evidence that MIDs can vary by scale, direction of change, cancer type and estimation method has raised doubt about a single global standard. This paper identifies MID patterns for interpreting group-level change in EORTC QLQ-C30 scores across nine cancer types.

METHODS

Data were obtained from 21 published EORTC Phase III trials that enroled 13,015 patients across nine cancer types (brain, colorectal, advanced breast, head/neck, lung, mesothelioma, melanoma, ovarian, and prostate). Anchor-based MIDs for within-group change and between-group differences in change over time were obtained via mean change method and linear regression, respectively. Separate MIDs were estimated for improvements and deteriorations. Distribution-based estimates were derived and compared with anchor-based MIDs.

RESULTS

Anchor-based MIDs mostly ranged from 5 to 10 points. Differences in MIDs for improvement vs deterioration, for both within-group and between-group, were mostly within a 2-points range. Larger differences between within-group and between-group MIDs were observed for several scales in ovarian, lung and head/neck cancer. Most anchor-based MIDs ranged between 0.3 SD and 0.5 SD distribution-based estimates.

CONCLUSIONS

Our results reinforce recent claims that no single MID can be applied to all EORTC QLQ-C30 scales and disease settings. MIDs varied by scale, improvement/deterioration, within/between comparisons and by cancer type. Researchers applying commonly used rules of thumb must be aware of the risk of dismissing changes that are clinically meaningful or underpowering analyses when smaller MIDs apply.

Minimally important differences for interpreting European Organisation for Research and Treatment of Cancer (EORTC) Quality of life Questionnaire core 30 scores in patients with ovarian cancer

INTRODUCTION

Minimal important differences (MIDs) are useful for interpreting changes or differences in health-related quality of life scores in terms of clinical importance. There are currently no MID guidelines for the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire core 30 (EORTC QLQ-C30) specific to ovarian cancer. This study aims to estimate MIDs for interpreting group-level change of EORTC QLQ-C30 scores in ovarian cancer.

METHODS

Data were derived from four EORTC published trials. Clinical anchors for each EORTC QLQ-C30 scale were selected using correlation strength and clinical plausibility. MIDs for within-group change and between-group differences in change over time were estimated via mean change method and linear regression respectively. For each EORTC QLQ-C30 scale, MID estimates from multiple anchors were summarized via weighted-correlation. Distribution-based MIDs were also examined as supportive evidence.

RESULTS

Anchor-based MIDs were determined for deterioration in 7 of the 14 EORTC QLQ-C30 scales assessed, and in 11 scales for improvement. Anchor-based MIDs for within-group change ranged from 4 to 19 (improvement) and - 9 to -4 (deterioration). Between-group MIDs ranged from 3 to 13 (improvement) and - 11 to -4 (deterioration). Generally, absolute anchor-based MIDs for most scales ranged from 4 to 10 points.

CONCLUSIONS

Our findings will aid interpretation of EORTC QLQ-C30 scores in ovarian cancer and inform sample size calculations in future ovarian cancer trials with endpoints that are based on EORTC QLQ-C30 scales.

Determination of the minimally important difference (MID) in multi-biomarker disease activity (MBDA) test scores: impact of diurnal and daily biomarker variation patterns on MBDA scores

The Multi-Biomarker Disease Activity (MBDA) score is a validated rheumatoid arthritis (RA) disease activity measure based on 12 serum biomarkers. Here, we evaluate short-term biological variability of MBDA scores to determine the magnitude of change that might be considered clinically meaningful. Twenty-eight adult seropositive RA patients with clinically stable disease and no changes in RA medications for 4 weeks prior to study were enrolled. Nine serum samples were obtained over four consecutive days (non-fasting). MBDA score variation was assessed day-to-day (daily) and within 24 h (diurnal). The standard deviation (SD) of MBDA scores was calculated by a linear mixed model including random effects for patient, day, and time of day. The minimally important difference (MID) was calculated as [Formula: see text]. A subgroup analysis was performed for patients with active RA (moderate or high MBDA score). The SD of MBDA score change in the full cohort was 4.7 in a combined daily-diurnal variation analysis, which corresponds with an MID of 11. The SD of MBDA score change in the subset of patients with active RA (moderate/high MBDA scores) was 3.6. This corresponds with an MID of 8 units in patients with active RA for whom clinicians are most likely to need guidance with respect to therapeutic decisions. Changes in MBDA score ≥ 8 represent a change in RA disease activity that clinicians can use as a benchmark for therapeutic drug efficacy and can be incorporated into a treat-to-target strategy.

ASPECTS OF PATIENT REPORTED OUTCOMES IN RARE DISEASES: A DISCUSSION PAPER

OBJECTIVES

A patient reported outcome (PRO) is "any report of the status of a patient's health condition that comes directly from the patient without interpretation of the patient's response by a clinician or anyone else" (USFDA 2009). PROs are discussed widely, and many regard the patients' perspective on treatment benefit as very valuable. Although many PROs have shown satisfactory measurement properties including reliability, validity, and responsiveness, there is great concern about risk of bias, that is, in clinical trials.

METHODS

Differences in perspectives of PRO measurement in rare diseases are given arising from methodology, clinical, HTA, and patient advocacy views.

RESULTS

PROs are playing an important role in dealing with treatment benefit especially in small sample size as occurring often in rare diseases. Challenges remain especially regarding lack of responsiveness of generic measures, limited capture of all patient relevant aspects, study design and high risk of bias.

CONCLUSIONS

PROs seem a valuable instrument to detect patient relevant aspects in rare diseases. They should be seen in addition to other approved assessment methods as randomized controlled trials but not as their substitute.