Relative importance measures for reprioritization response shift.
OBJECTIVE
Response shift (RS), a change in the meaning of an individual's self-evaluation of a target construct, such as health-related quality of life (HRQOL), can affect the interpretation of change in measures of the construct collected over time. This study proposes new statistical methods to test for reprioritization RS, in which the relative importance of HRQOL domains changes over time.


METHODS
The methods use descriptive discriminant analysis or logistic regression models and bootstrap inference to test for change in relative importance weights (method 1) or ranks (method 2) for discriminating between patient groups at two occasions. The methods are demonstrated using data from the Manitoba Inflammatory Bowel Disease (IBD) Cohort Study (n = 388). Reprioritization of domains from the IBD Questionnaire (IBDQ) and SF-36 was investigated for groups with active and inactive disease symptoms.


RESULTS
The IBDQ bowel symptoms and SF-36 bodily pain domains had the highest ranks for group discrimination. Using Method 1, there was evidence of reprioritization RS in the IBDQ social functioning domain and the SF-36 bodily pain and social functioning domains. Method 2 did not detect change for any of the domains.


CONCLUSIONS
Compared to IBD patients without active disease symptoms, those with active symptoms were likely to change the meaning of their self-evaluations of pain and social interactions. Further research is needed to compare these new RS detection methods under a variety of data analytic conditions before recommendations about the optimal method can be made.
School of Public Health, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK, S7N 5E5, Canada. lisa.lix@usask.ca
Lisa M
LM
Lix
Tolulope T
TT
Sajobi
Richard
R
Sawatzky
Juxin
J
Liu
Nancy E
NE
Mayo
Yuhui
Y
Huang
Lesley A
LA
Graff
John R
JR
Walker
Jason
J
Ediger
Ian
I
Clara
Kathryn
K
Sexton
Rachel
R
Carr
Charles N
CN
Bernstein
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D016002:Discriminant Analysis; D005260:Female; D006304:Health Status; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology*; D016015:Logistic Models; D008297:Male; D008350:Manitoba; D008875:Middle Aged; D010146:Pain; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018434:Sickness Impact Profile; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires / Q000592:standards