Responsiveness and convergent validity of QLU-C10D and EQ-5D-3L in assessing short-term quality of life following esophagectomy
Authors: Bulamu Norma B. , Vissapragada Ravi , Chen Gang , Ratcliffe Julie , Mudge Louise A. , Smithers B. Mark , Isenring Elizabeth A. , Smith Lorelle , Jamieson Glyn G. , Watson David I. ,   The Australian Immunonutrition Study Group, Mudge Louise A. , Bessell Justin , Barbour Andrew , Isenring Elizabeth A. , Aly Ahmad , Archer Stephen , Ballal Mohammed , Barbon Jessica , Benton Katie , Bond Melissa , Berryman Melissa , Bright Tim , Cade Richard , Cardamis Anna , Carroll Rosemary , Cashman Kara , Chan Larissa , Chapman Brooke , Chapman Sally , Chen Derek , Chisholm Jacob , Davidson Wendy , Devitt Peter , Dong Cuong , Doola Ra’eesa , Edwards Suzanne , Epari Krishna , Farley Maree , Farrow Julie , Ferguson Maree , Fletcher David , Forbes Kerry , Fullerton Katherine , Game Philip , Gan Susan , Gotley David , Gout Belinda , Gray Jodi , Heaney Susan , Jamieson Glyn G. , Johnson Mary Anne , Johnstone Megan , Kariyawasam Sanjeeva , Karnon Jonathan , Kelaart Amber , Kellett Liz , Kennedy Erin , Krane Rhiannon , Lemass Sylvia , Loeliger Jenelle , Lord Andrew , Ludbrook John , McFarlane Catherine , McPhee Michelle , Ooi Selena Yue-Xian , Pearce Leonie , Pettigrew Kate , Putrus Emma , Rassias Georgina , Shanks Alison , Shenfine Jon , Smith Emma Louise , Smith Lorelle , Singleton Justin , Smithers B. Mark , Lindstrom-Sowman Rebecca , Spillane John , Sputore Liliana , Steer Belinda , Sullivan Tom , Teleni Laisa , Tolcher Deb , Thomas Janine , Thompson Sarah , Thorpe Tina , Watson David I. , Watterson Cheryl , Wills Vanessa , Wilton Anita , Wright Kellie , Wright Tim 
Published: October 2021

Abstract
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 health related quality of life (HRQoL) outcomes after esophagectomy.

Methods
Participants were enrolled in a multicentre randomised controlled trial to determine the impact of preoperative and postoperative immunonutrition versus standard nutrition in patients with esophageal cancer. HRQoL 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 at follow-up/post-operatively. Convergent validity was assessed using Spearman’s correlation and the level of agreement was explored using Bland–Altman plots.

Results
Data from 164 respondents (mean age: 63 years, 81% male) were analysed. HRQoL significantly reduced on both measures with large effect sizes (> 0.80), and a greater mean difference (0.29 compared to 0.16) on QLU-C10D. Both measures had ceiling effects (> 15%) on all dimensions at baseline. Following esophagectomy, ceiling effects were observed with self-care (86%), mobility (67%), anxiety/depression (55%) and pain/discomfort (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.

Conclusion
The QLU-C10D is comparable to the more widely applied generic EQ-5D-3L, however, 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, the disease-specific QLU-C10D should be used alongside the generic measures like EQ-5D-3L.
Trial registration: The trial was registered with the Australian New Zealand Clinical Trial Registry (ACTRN12611000178943) on the 15th of February 2011.