Response Shift In Quality Of Life Measurement In Patients With Hypertension In The Community

1. Background:As the Medical Model changed from biomedical model to biopsychosocial medical model, the Quality of life (QOL) measurement has been more and more important in social and medical clinical research. An emerging construct of relevance to this line of investigation is response shift phenomenon. Response shift has been defined as 'a change in the meaning of one's self-evaluation of a target construct as a result of: (a) a change in the respondent's internal standards of measurement (i.e. scale recalibration); (b) a change in the respondent's values (i.e. reprioritization, the change of importance of component domains constituting the target construct); (c)a redefinition of the target construct(i.e. reconceptualization)'. It can occur in any self-reported outcome measurements. As a self-reported outcome, QOL can mean different things to different persons at different time. That's to say, the intra-individual standard could change. Measurement of change in QOL will be inaccurate if response shift is present due to recalibration, reprioritization or reconceptualization over time from pre to post measurement. Thus, changes may be incorrectly interpreted if response shift is not taken into account. Response shift can be a confounding factor. In other instances, such as self-management and psycho-social programs, rehabilitation, and palliative care, response shift may be a planned or anticipated effect of interventions. In these conditions, response shift is a desired outcome. Response shift must therefore be taken into account when using measurement to assess the change of QOL. Ⅱ. Objectives:The purpose of this study was to examine the role of response shift in patients with hypertension in the community disease management program. Traditional and response shift adjusted change of QOL were compared to evaluate the impact of response shift in the QOL change. Direction of response shift and factors influencing response shift in patients with hypertention are explored.Ⅲ. Methods:1. Select subjects: On given days chosen by researcher, all consecutive patients with hypertension in the community disease management program were invited to self-administer the survey.2. Then test design were used to detect the recalibration response shift. Select subjects completed a Short Form-36 ( SF-36) Health Survey and a EuroQol ( EQ-5D) questionnaire preoperatively (time 1 test). After 4 weeks' disease management program intervention, the patients completed two questionnaires: one on how they felt currently (time 2 test), and one on how they perceived themselves to have been 4 weeks ago (then test).3. EpiData3.1 were used for data entry. Descriptive statistics, factor analysis, paired t test, nonparametric tests, partial correlation analysis, hierarchical multiple regression of variances and other methods were used for data analysis with software SPSS 15.0.Ⅳ. Results:1. The study cohort comprised 215 subjects, including one hundred men and one hundred and fifteen women, with a mean age (and standard deviation) of 66.2±12.0 years.2. About half of the patients have response shift in each domains of QOL. The direction of response shift varies. There are positive, negative recalibration response shift and no response shift in different patients. At the group level, a significant (p < 0.05) response shift was observed in the SF-36 domains of physical function, role-physical, body pain, social function and physical component summary score, then test scores are higher than time 1 scores in those domains.3. In measuring outcome, traditional change(time 2 scores minus time 1 scores) is significant larger than the response shift adjusted(ime 2 scores minus then test scores) change of QOL.4. Patients with positive recalibration in VAS have higher baseline mental health, and have gain a significant improvement from time 1 to time 2 in mental health, while patients with negative recalibration and no recalibration have no significant improvement in mental health. There are no significant differences in baseline physical health among different patients with different recalbration direction.5. After controlling for the Time 1 score, age and education explained a small but significant amount of variance in response shift in most of the domains of QOL.Ⅴ.Conclusion:Response shift phenomenon happened in patients with hypertension in the community disease management program. The traditional pre- and post-assessment of program effect may be confounded by a change in internal standards of measurement in patients with hypertension. Different directions of recalibration have different impacts on the change of QOL. Positive recalibration could improve the mental health. The change of QOL can be better understanded when response shift be taken into account. There are many aspects of response shift which require further study, such as improving the theoretical underpinnings of response shift, evaluating the validity of current and emerging methods, identifying those who potentially underwent response shift, et al.As for the community disease management program, positive recalibration response shift can be a desired outcome to improve the QOL of patients with hypertension in community disease management program.