Aim: This study assessed the responsiveness and convergent validity of two preference-based measures; the newly developed cancer-specific EORTC Quality of Life Utility Measure-Core 10 dimensions (QLU-C10D) relative to the generic three-level version of the EuroQol 5 dimensions (EQ-5D-3L) in evaluating short-term quality-of-life outcomes/utilities after esophagectomy.
Methods: Participants were enrolled in a multicentre 2×2 factorial randomised controlled trial to determine the impact of preoperative and postoperative immunonutrition versus standard nutrition in patients with esophageal cancer. Quality-of-life was assessed seven days before and 42 days after esophagectomy. Standardized Response Mean and Effect Size were calculated to assess responsiveness. Ceiling effects for each dimension were calculated as the proportion of the best level responses for that dimension. Convergent validity was assessed using Spearman’s correlation and the level of agreement was explored using Bland–Altman plots. Regression analysis was performed to identify which demographic and clinical factors influenced quality of life.
Results: Respondents were 164, predominantly male (81%) with mean age of 63 years. Quality-of-life significantly reduced on both measures with large effect sizes (>80), and greater mean difference on QLU-C10D. Ceiling effects were observed with social activities (86%), mobility (67%), anxiety (55%) and pain (19%) dimensions on EQ-5D-3L. For QLU-C10D ceiling effects were observed with emotional function (53%), physical function (16%), nausea (35%), sleep (31%), bowel problems (21%) and pain (20%). A strong correlation (r=0.71) was observed between EQ-5D-3L anxiety and QLU-C10D emotional function dimensions. Good agreement (3.7% observations outside the limits of agreement) was observed between the utility scores. Blood loss and blood transfusion predicted EQ-5D-3L utility while smoking and tumour length >3cm were predictive of QLU-C10D utility. Changes in QLQ-C30 dimensions of emotional function, role function and pain were predictive of changes in EQ-5D-3L utility while changes in physical, social and role function as well as all the symptom scales were predictive of change in QLU-C10D utility.
Conclusion: Although there is strong agreement between utility scores, QLU-C10D was more sensitive to short-term utility changes following esophagectomy. Cognisant of requirements by policy makers to apply generic utility measures in cost effectiveness studies, disease-specific measures should be used alongside the generic measures.
The trial was registered with the Australian New Zealand Clinical Trial Registry (ACTRN12611000178943) on the 15th February 2011.